Portal may be one large Nice Job Breaking It, Hero, if GLaDOS's claim is to be believed. She implies, during the final battle, that the Combine invasion that led up to Half-Life 2 is going on at that moment. "All I know is I'm the only thing standing between us, and them... Well... I was." But then, one must consider the source of the claim.
Also implied in "Lab Rat", a tie-in comic that acts as a bridge between the game and its sequel: GLaDOS may have been a nasty piece of work, but she kept the facility running. When you blew her up, you turned off the cryochambers, rendering the 10,000 subjects that were supposed to test after you dead. On the plus side, you did get to pass out in a parking lot.
Ironically, when GLaDOS actually says this, it is not an example of the trope... it is said directly after you destroy one of her vital parts in the final boss battle. She feebly tries to convince you that "it made shoes for orphans".
In Portal 2, the player winds up making another one by giving literal Idiot Ball Wheatley control of the entire facility via core transfer, which would eventually bring its destruction (and the protagonist's death) through management incompetence. GLaDOS, of course, sarcastically comments on this, never mind that she'd just committed a major whoopsie by taunting Wheatley until he smashes both of you down a nearly bottomless pit.
GLaDOS: CLAP...CLAP...CLAP "Oh good, my slow clap processor made it into this thing. So we have that."
GLaDOS begins the first game as a slightly insane testing computer whose homicidal tendencies are frustrated by Restraining Bolts. Through Chell's efforts, she ends the second game completely unfettered — possibly to the point of having deleted her conscience — and unchallenged, and in charge of a weapons manufacturing facility that could be the greatest military power on post-Combine Earth. Depending on how future Portal games pan out, this might prove to have been a colossally terrible move.
That depends on if she's telling the truth about deleting Caroline. And if she plans on expanding beyond testing, of course.
Dead or Alive: As shown in the Dead or Alive Ultimate intro video, Hayate, in an attempt to stop Raidou from stealing the Torn Sky Blast, elects to use that very technique on him. The minute he does so, Raidou copies the technique and proceeds to win a Beam-O-War against Hayate, resulting in Hayate suffering a broken spine... which also leads to Kasumi's Roaring Rampage of Revenge against Raidou and subsequent exile from the Mugen Tenshin Clan. On top of it all, Ayane even explicitly warned Hayate not to use the Torn Sky Blast against Raidou, but Hayate did it anyway.
"Shounen Kininden Tsumuji" Tsumuji is tricked by the Big Bad and uses his Shuriken to make the Shadow Tower rise which grants the villian to enter the Demon Castle in the sky to continue his plan to rule the world.
Alex Mercer does everything to further the villain's plans. Where to begin? Releasing Elizabeth Greene would cause the virus to spread further, collecting the genetic material for the supposed cure turns out to be a parasite for him to be injected, and helping Cross, who is the Supreme Hunter in disguise, get to Randall.
Another two incidents which Helena Pierce calls you out on: One-Eyed Jack's vow of vengeance after you destroy his stock and killing Jaynis Kobb and allowing his brother Taylor to make Jaynistown into an even greater threat.
The entirety of Borderlands 2 is this trope because of what happened in the first game. Thanks to you opening the Vault and effectively destroying corrupt Mega Corp. Atlas, Pandora has an alien element called Eridium that is very powerful in certain uses and is extremely valuable. The head of Hyperion, Handsome Jack, took over Pandora now that Atlas is no more and has capitalized on Eridium while taking credit for the find and attempts to kill the Vault Hunters from the first game. Thanks to Hyperion's presence, the people of Pandora live shittier lives due to the corporation destroying everyone's livelihoods and killing anyone that they damn well please, especially anyone that opposes them, while the company destroys the planet further with constant mining for Eridium and the search for a 2nd Vault. Whoops!
Within Borderlands 2: Roland and Angel both urge Lilith to not be anywhere near the Hyperion base you are assaulting in attempt to retrieve the Vault Key from Jack. This is because Jack needs a Siren to charge the key. Part of your objective becomes dealing with Jack's current Siren to make sure that, even if he gets the key back, he can't charge it. Naturally, Lilith defiantly shows up at the end of the attack. This puts her in the perfect position for Jack to swoop in, capture her, and put her right to work charging the key. Because of her arrival, all of your effort not only barely interrupted Hyperion's progress, but gave them a stronger Siren to accelerate the process. Good job, Lilith, though technically it's Angel's fault for not precisely telling her that it was a trap. Good job letting your fear of your dad ruin two lives there, Angel.
Arc The Lad: Twilight of the Spirits has a very annoying example. The guy whose life you saved at the beginning? The one you get a Game Over if you don't save? Who then helps you out on your quest? Turns out he's the Big Bad all along, and all you've been doing the entire game with both of your parties was being the MacGuffin Delivery Service, just as he planned. He takes them all, and raises the evil fortress. The world would have been much better off if you had just let the guy die when he was helpless.
Xenosaga has an epic example of this. The Gnosis, who've been rampaging throughout the known universe, killing all human beings in their path, and generally terrorizing the galactic community? Guess who summoned them? As it turns out, it was Shion herself, in a Big "NO!" moment.From Bad to Worse. When Shion finds all of this out, the breakdown she suffers causes her to have another Big "NO!", which summons Abel's Ark. This causes her to suffer a Heroic BSOD of epic proportions.
In Trauma Team, in the last chapter, we find out that Albert Sartre killed his own daughter to attempt to stop the spreading of the Rosalia virus. Turns out that this allowed the virus to spread from her blood to flowers, to butterflies, infecting a whole city and threatening to exterminate mankind. Nice job breaking it, Doc.
And then, at the end of Ocarina of Time, Zelda sends Link back in time to his childhood to prevent Ganondorf's rise to power. This splits the timeline in two, and while Ganondorf is successfully thwarted in the "Child" timeline, Zelda ensures that the timeline she herself is in lacks a Hero, and as such dooms 90% of the population of her Hyrule to death by drowning in the Great Flood. Nice job protecting (your own) Hyrule, princess.
In fact, most of the games featuring the Master Sword use this - the Master Sword is a "key" to the Sacred Realm/Golden Land where Ganondorf/Ganon is held captive, and in the process of collecting the sword to defeat the beginnings of his influence, the player releases him fully.
The Legend of Zelda: Twilight Princess does a fairly good job of not breaking things: although the Dragon is still able to grab the Fused Shadows, grabbing the Master Sword actually doesn't unleash some kind of unspeakable evil on the world. Someone else already did that.
More specifically, the Sages pulled a good one when they failed to destroy Ganondorf and then exiled him to the Twilit Realm out of desperation. Of special note is the fact that two realms were put in imminent danger, instead of just Hyrule. Link just winds up having to clean up the mess. Again.
In The Legend of Zelda: Link's Awakening, Link goes through the game defeating the Nightmares, which are creating all the monsters that are rampaging around Koholint Island, and in doing so he collects the Instruments he'll need to wake the Wind Fish so that he can escape the island. Unfortunately, Koholint was just a dream the slumbering Wind Fish was having. So as soon as Link wakes him, the island and its people vaporize. This is actually shown in a poignant ending scene, while the Ballad of the Wind Fish plays. In fact, the last thing we see is Marin singing along to the Ballad while she and the world around her fade into oblivion.Nice Job Waking It, Hero. Subverted in that Link KNEW that waking the Wind Fish would destroy the island. He was told several times and reminded about it by the Nightmares. Except that almost all the warnings Link gets (which are not until the game is about 75% over) come from the Nightmares. So let's see: an evil, horrible, murderous entity that's polluting the world with monsters tells you something that would prevent you from killing it (which is otherwise your main goal). Are you likely to believe it? The only other warning he gets is an ancient tablet—which his guide/advisor immediately tells him may not be accurate.
IF you finish the game without dying once, one of the shots of seagulls flying during the end credits is replaced by a shot of Marin's Sprite flying around on wings, hinting that she got her wish of becoming a seagull and was able to leave the island.
In Zelda II, the game's story strongly suggests that life in Hyrule has become even worse since the (very) first game, because now, nobody is controlling Ganon's monsters. Blame Link.
It doesn't help that of all things, the one thing said monsters can focus on is that by killing Link, they can revive Ganon. So, assuming you fail in your quest (which you probably will; this isZelda II after all), you get to unleash Ganon BACK upon the world, this time with no Link to stop him. Nice Job.
A similar event happens for the 3rd timeline of Ocarina of Time; Hyrule Historia indicates that the 3rd timeline in the split was created by Link's defeat against Ganon, which starts the timeline leading to A Link to the Past. So if you lost against Ganon in Ocarina of Time, you just doomed Hyrule for another several generations!
In The Legend Of Zelda Oracle of Ages, the first thing Link does is push away the barrier rock that keeps out all evil from Nayru's glade, and leads the villain, Veran (who is possessing Impa's body) in, trying to help her. The second thing that happens is that the Veran kidnaps Nayru, laughs at Link for being so stupid, and makes off with her.
In The Legend of Zelda: Skyward Sword: Congratulations, Link! You not only managed to get your hands on the Triforce, and you used it to crush the Imprisoned into powder in such a way that he isn't coming back! Now, we all know Ghirahim is still out there, so before you pay Zelda a visit, why don't you just, you know, follow Impa's lead and blow up the Gate of Time?!
Not only does he allow the aforementioned to happen, but in the side quests, he literally breaks a chandelier just to obtain a heart piece, makes a Kikwi become a Skyloft professor's science project, tricks the elder Mogma into becoming the Lumpy Pumpkin's slave, and — worst of all — forces Cawlin to endure humiliation and night terrors just so that he can get some gratitude crystals for Batreaux. This LP sums it up perfectly, making us wonder if Link is more capable of breaking things than he is fixing them. What the Hell, Hero?, indeed.
SaGa Frontier: Riki's Scenario: You know those rings the elder asked you to get? It turns out that they corrupt the wish of the user, which leads to the inhabitants of Margmel disappearing, as they were not around when Margmel was born.
Also, thanks to the Queen, no one ever knew about the mask. Two of the hero's companions are her friggin' son and one of the heroes who helped defeat Xiphos for the first time, and even they had no clue.
The Elder Scrolls IV: Oblivion makes use of this trope. In the Benirus Manor quest, the undead former owner wishes to repent and can only do this if you put his severed hand back on his corpse — which is in fact a Batman Gambit, and releases a (semi-)powerful lich against you and the rest of the town/world etc.
A subversion is also shown throughout the later Dark Brotherhood quests, as the player believes that they are killing targets, when in actual fact they are systematically killing off all the Higher-Ups of the Brotherhood. 'Well done Hero, Nice job killing our leader'. But the Night Mother knew about the plot all along, but she figured that if the Black Hand weren't smart enough to weed out the traitor in their own ranks, they didn't deserve to live anyway.
Golden Sun: Dark Dawn brings us the raid on Belinsk, which is a chain of turning it From Bad to Worse. What began as an infiltration of Belinsk castle (orchestrated by Sveta behind the scenes), ends up a massive detour through the underground ruins to the Alchemy Dynamo. Traps are set off all the way to the entrance of the dynamo facility to keep the party on rails, but nothing compares to the end. Ryu Kou winds up using the Magma Orb hesitantly, only to be forced into going all the way thanks to Arcanus' intervention, and the end result is the raising of Eclipse Tower. Things go straight to hell after you bail Hou Ju and Eoleo out, as the sun rises and, due to the inevitable alignment, harmonizes with the tower to cause the Grave Eclipse. The beastmen who haven't fled are intercepted and killed by monsters in very short order, Volechek stays behind to atone for his erroneous judgment (and this is a ways after we learn that Sveta's his younger sister), and Briggs keeps his ship docked at the port to save the party at the cost of his life. The party — and Ryu Kou — can be forgiven due to the fact that they were railroaded into this. The Tuaparang, on the other hand, cannot. Still, fuck you, Alex.
And in a more literal meaning of this, one of the main characters breaks the hard-to-make glider by trying to "test" it in the beginning of the game. The other two heroes and the two male kids' fathers have to save him.
Alex also made the main characters play right into his hands AGAIN, as by using the Apollo lens, they have just helped to further his master plan.
In Metroid: Fusion, the Metroids — a species of highly dangerous alien creatures — have been virtually eliminated from their homeworld by the protagonist; it turns out that the Metroids were keeping a terrible shape-shifting parasite in check, and now it's overrun the planet, forcing the protagonist to deal with it. Whoops.
Fusion also cleverly averts this trope, with the same intent as the failed Metroids above. Samus attempts a Heroic Sacrifice in order to destroy the remaining SA-X on the station. The AI "Adam" stops her, reminding her that there's still more X on the planet below.
"Adam": How foolish. Even if you are successful in destroying the station, you'll only remove the one thing between the X and total universal domination: yourself.
Again in Fusion, Samus opens the door to a secret lab where Metroids are being cultivated... allowing a replicant SA-X to waltz in and wreck it. It loops back to Nice Job Fixing It, Villain when the Metroids are let loose on the ship and start predating the X, eventually killing the original SA-X and letting Samus get her Ice Beam back from it.
Subverted in Metroid Prime Hunters. Upon finally finding the Ultimate Power, it is revealed to actually be the Eldritch Abomination Gorea. The hunters set it free, only for Samus to immediately kick its ass.
Near the end of Ultima Underworld, the protagonist finally cuts down the evil Big Bad wizard... only to have the wizard reveal, as he dies, that he's been keeping an invincible demon in perpetual confinement in a chamber below, and with his death, the confinement spell will fade shortly, but not too shortly. Now the hero has to run down and find a way to banish the demon for good before it breaks loose and destroys the world. Whoops.
In the main Ultima series, the Avatar does end up being responsible for the eradication of (almost) all human life on both Serpent Isle and Pagan, in Ultima VII Part II and 8 respectively. Also, after the fourth game, the king Lord British has the Codex Of Ultimate Wisdom raised from the underworld, which is the direct cause for the gargoyle invasion in Ultima VI. The other games in the series are simply the revenge of some ally of the previous Big Bad. Ultima IX does claim that the Avatar's quest for virtue in Ultima IV was what created the Guardian (Big Bad of games 7-9), but U9 is generally considered Canon Discontinuity anyway.
In Ultima I, after shattering Mondain's gem of immortality and killing Mondain. Neither Lord British or the pre-Avatar properly dispose of the gem shards... let's hope no-one finds it and becomes corrupted by it becoming an evil tyrant as well as unleashing 3 demons of sin onto the world... oh crap... Ultima V.
Happens twice in Drakengard 2. First the destruction of the Knights and their seals unleash a red dragon that intends to destroy the world. And then, when you kill the red dragon, it turns out that it was a seal for the dark gods that control the world. And the sky explodes. Whoops indeed.
In ending four of the original Drakengard, the heroes kill the Big Bad, Manah, while she's still the instrument of the gods, killing the gods in the process. Turns out that even though the gods are evil Cosmic Horrors that want to destroy the world, they're also keeping the world in some semblance of order... And without them, giant, flying, plasma-breathing, man-eating babies descend from the sky. Really.
It's implied that said man-eating babies are the gods, who are pissed off at their instrument being destroyed.
Ending E's ramifications aren't immediately apparent, but give way to the events of NieR, where our world is ruined.
In the end of Half-Life 2, Gordon's attempt to stop Breen from teleporting off-world, while successful, results in the partial destruction of the Citadel — so that the Combine decide to sacrifice the Citadel (and thus destroy what's left of City 17) to open a superportal and send reinforcements to Earth.
It gets worse in Half-Life. Killing the Nihilanth? His death throes amplify the resonance cascade, so the Combine see a giant INVADE HERE sign, so they pop through the borderworld and eventually appear in our dimension. Add to that Gordon had recently launched a satellite that allowed the Combine to open portals all over the Earth AND the fact that he also started the resonance cascade, and it becomes more difficult to cheer him on as the atrocities pile up...
Prior to the announcement of the sequel, Half-Life 1's ending appeared to be that the US government had deliberately engineered the resonance cascade to provoke an alien war that, judging by the army bodies seen on Xen during G-man's final speech, coupled with him saying "the border world, Xen, is under our control now, thanks to you", ended with a military conquest of the alien world. Which is still something of a Nice Job.
In Mortal Kombat Deception, Shujinko spends over 40 years collecting the Kamidogu for the Elder Gods, only to find that he had been serving the Dragon King Onaga all along when Onaga is resurrected. He then embarks on a quest to undo the evil he unleashed on the realms.
Later, in Mortal Kombat Armageddon, Argus and his wife Delia are charged with preventing The End of the World as We Know It, setting up their sons and a firespawn of their own creation as the keys to stopping the disaster. Too bad they left their project to run its course unsupervised, otherwise the firespawn wouldn't have been captured and corrupted, one of their sons wouldn't have woken up early with a grudge and slaughtered them, and as a result, their entire plan wouldn't have been the very catalyst of the apocalypse they were trying to prevent. It's called "parental supervision" for a reason, Argus.
Argus and Delia created a safeguard against the coming Armageddon, a powerful chestpiece. Argus was going to make it kill everyone, but Delia didn't approve, so instead it was created to randomly either kill everyone or depower them, and you never know exactly what it will do, until it's finally used and DOESN'T DO A DAMN THING. Nice job breaking it, saviors of humanity.
Moreso in the actual Mortal Kombat 9: Raiden saving Smoke form being roboticized? They got Sub-Zero instead. Raiden kills Motaro and saves Johnny Cage? Cue Shao Kahn transferring Shang Tsung's own soul and the myriad of souls he's absorbed into Sindel, which results in her going on a rampage, killing a boatload of Earthrealm heroes, the aforementioned Smoke included. To make matters worse, Quan Chi has now enslaved the multitude of those who died in the aforementioned rampage, making them his mindless zombies. Sure it worked, since Cage and Sonya Blade survived, but still, Nice Job Getting Most Of The Good Guys Killed And Enslaved By Quan Chi And Leaving Earthrealm And Outworld Vulnerable To Shinnok, Raiden!
Final Fantasy IV: Cecil gives Golbez the Earth Crystal in exchange for his girlfriend, which only helps him out in his plan for world conquest. Then they perform anotherMacGuffin Delivery Service. At the end of the game, defeating Zemus causes his leftover hatred to become Zeromus.
Final Fantasy V: The heroes have already failed to stop Exdeath from breaking the crystals of their world, and then they go and kill the Crystal Guardians of the other world, letting Exdeath complete his evil plan. Near the end, killing Exdeath turns him into the near-omnipotent destructive nihilist Neo-Exdeath. (Speaking of which, who thinks up these names, anyway?)
Final Fantasy VI: Gaining the Espers' trust and bringing them to Thamasa for a supposed reconciliation with The Empire just allows Kefka to massacre them all and become more powerful.
Plus, he probably wouldn't have upset the balance of the Statues, thus setting off The End of the World as We Know It, if Celes hadn't stabbed him right before then. (Or stabbed a bit more accurately and finished him off right there, I suppose.)
Final Fantasy VII: The heroes retrieve the Black Materia in order to keep it away from Sephiroth, but once it's been unsealed, he just mind-controls Cloud into giving it to him.
You also kill Jenova so Holy can stop Meteor, but Holy ends up making things even worse until the Lifestream pops up to save the day. Sure, all this happens in the end cutscene without the player having any control, but still.
Final Fantasy VIII: Squall and the party decide to bring the comatose Rinoa to Esthar, where Odine comes forth with the idea to send her to the Esthar Lunar Base because of its advanced medical technology. Once there, Ultimecia's conscience uses Rinoa's body to release Sorceress Adel from her cryo-tomb. Nice job breaking it, Odine.
Final Fantasy X: Surprisingly inverted, sort of. After killing the keeper of the Final Aeon, rather than using said Aeon to temporarily solve the problem, your merry group instead finds a way to end it permanently. Way to actually fix it, hero!
Final Fantasy XIII: In Chapter 9, the party learn that Barthelandus is the Puppet Master, and he explicitly tells the party that their Focus is to kill Orphan, destroying Cocoon in the process. In Chapter 13, they kill Barthelandus, thinking that that will save Cocoon, but doing so wakes Orphan. Learning that Orphan's purpose is to bring about Cocoon's destruction, the party kills Orphan, destroying Cocoon in the process. Strange for a game whose central theme was free will. The only upside to the heroes doing it their way is that at least some of humanity survives.
The sequel has this too: Noel refuses to kill Caius, but the latter just grabs on to his sword and kills himself. That's good, right? Wrong! It turns out that Noel just killed the Heart of Chaos, the manifestation of Etro. Thanks to that, the whole world is doomed. Oops...
Still in Final Fantasy XIII-2, Hope leads the project to create an artificial fal'Cie and use its power for the benefit of the people of the city of Academia. Unfortunately, all he manages is to create a GLaDOS-like AI that kills him and the entire research group (which were replaced by artificial copies by the AI to cover up the incident), and leaves Academia at its mercy. Oops. Did I mention that it can turn people into undead Cie'th WITHOUT marking them and giving them a Focus first? Double oops...
Final Fantasy Tactics is more or less a long string of these (as in, you're doing it for most of the game, if not all of it). In particular...
Ramza and company saving Algus and Elmdor, both of which come back to haunt you later.
Ramza leaving the Zodiac Stones he'd gathered with his defenseless, kidnap-prone sister. At first, this seems like a minor oops that only nets the enemy a few stones. Then, during her inevitable captivity, she is found by the bad guys and identified as the perfect vessel to stuff their dead leader into, speeding up their plan by hundreds of years. Granted, there's no way Ramza could have seen this coming, but the act itself was stupid enough to warrant a 'nice job'.
Ramza insisting his sister stay in the monastery is another one. She tells him Ramza is a marked man, people know about him and her and will come after her. Ramza insists she stay, and surprise surprise, she gets kidnapped by people Ramza could easily beat up. Oh and despite being weak, she has a ridiculously broken buff skill that would have been hugely useful. Nice job....
Final Fantasy XIV has the player character fight against Garuda, a primal summoned by the Ixal beast tribe. The player defeats her, but the Ixal just prays harder and they cause Garuda to come back stronger than ever. The Ixal then slowly kill their Kobold and Amalj'aa hostages in order to cause them so much pain that they would summon their own primals (Ifrit and Titan) out of desperation and fear so that Garuda can absorb their power. After all three primals are present, your companions pull an Oh Crap moment as they now have to deal with three primals. Of course, things only get worse when The Empire shows up; Ultima Weapon shows up and the empire uses it to curbstomp the primals and absorb them to fully power up the ancient weapon. Naturally, you're tasked to stop it.
The 'Destiny Odyssey' section of the primary storyline of Dissidia: Final Fantasy revolves around each hero character from the first ten Final Fantasy games overcoming their respective adversaries to acquire a crystal. Turns out that each crystal contained a portion of Cosmos' power, which weakened her enough to allow Chaos to kill her. Whoops. Granted, it was all part of Cosmos' Thanatos Gambit, but a bit of a heads-up might have been nice.
An extremely common way of ensuring yourself a sequel. One example is Dungeon Siege 2.
In Guild Wars, you join the White Mantle and help them located gifted people... only to find out they're using them as human sacrifices. You then gain the power to combat the Mantle and their gods by allying with others... only to have your allies release something worse to kill the gods. And then, in finally ending the situation, you cause a volcano to explode.
Paralleling the above events was how you essentially fumbled about with the Scepter of Orr throughout the game. First the Mantle located and rescued it from the grasp of the Lich Lord, which was good. Then you stole it from the Mantle, which was also good since who knows what they would have done with it. Then you give it back to the Lich, though you didn't know at the time. And it turns out the Lich needed the Scepter to defeat the Mantle's gods... by unleashing even worse beings.
Not to mention when you free Palawa Joko, since he's going to conquer the place about half a century after Nightfall takes place (as revealed in The Movement of the World, an article about GW2). And seeing as the first thing he does after honoring your bargain is to start rebuilding his armies, you know what he's going to do.
All of the events of Nightfall took place because Kormir, the greatest hero of the Sunspears, did everything she was supposed to not do. And her reward for nearly destroying the world and getting hundred, if not thousands, of innocents brutally murdered in the crossfire is to become a god.
There are a lot of smaller examples, too.
After beating the Final Boss in Secret of Evermore, it's revealed that the hero's actions have disrupted the world's balance of good and evil, and the world will effectively implode unless it's fixed. Whoops...
In Prince of Persia: The Sands of Time, the Prince activates the palace's traps, only to realize too late that they will do absolutely nothing to hinder all the monsters running around and will only make his life more difficult. His Genre Blindness is lampshaded midway through the activation sequence when he asks the palace guardsman who told him to activate the defense system what, exactly, it's going to do. The guard responds that he told him, it'll activate the defense system. The Prince doesn't ask for clarification.
Not to mention releasing the Sands of Time in the first place. And causing the creation of the Sands themselves. And then undoing that, pushing the Reset Button, and bringing back the original villain and ruining his home town.
In the 2008 game, (another) Prince spends his entire time sealing back up an evil in a can and at the end decides to unleash it again and undo all that hard work. Subverted when explained in the epilogue that he had an excellent reason for doing that. Elika sacrificed herself to seal Ahriman away again. The problem with this is that seals can break, as was proven at the very beginning of the game. This seal will break again, and when it does, the one thing capable of truly destroying Ahriman — the power inside of Elika — won't be around to stop him. By unsealing Ahriman again on the condition that Ahriman resurrects Elika, the Prince has given the world a chance at getting rid of Ahriman for good. It's more of a potential Nice Job Fixing It, Villain in Ahriman's case for reviving Elika in exchange for his own freedom.
There's an even crueler one in Persona 4. Nice job saving your friends from dying inside the Midnight Channel, hero! Too bad the murderer is using your rescues as 'proof' to make the kidnapper (and yes, they're different people) convinced that the TV world really IS safe so he'll keep throwing people in. And now they've gotten so overzealous about the whole thing that they've taken your adorable cousin inside with them. Heck, your entire team can invoke this further if you choose to condemn the seemingly guilty kidnapper and throw him into the TV... which lets a Knight Templar goddess destroy the world.
You could also cement this in The Golden by destroying the letter in the Jester/Hunger Social Link.
The real fun part comes at the end, where Al-Mualim turns out to be behind everything, having Altaïr kill the Templars so that only he knew the secret to how to operate the Piece of Eden and thereby giving him absolute control of the Holy Land.
In the flash game, Fishy, you play as a fish with the goal of eating smaller fish, gradually becoming larger as you do so. If you go on long enough, the game abruptly ends, informing you that you've destroyed the pond's ecosystem by eating everything. Whoops.
In Haven Call Of The King, Haven spends most of the game trying to find a mystical golden bell that will summon the warrior King Athelion to save Haven's people from the tyranny of alien overlord Vetch. Haven reaches the bell and rings it. Shortly thereafter, his friend Chess calls and says she's been captured by Vetch, so Haven, thinking "My work here is done," heads off to save her. Then we find out that Chess is a spy working for Vetch, and Athelion doesn't come to the bell, but rather to the person who rang it. In this case, he'll come to Haven, who left Athelion's stronghold (where the King would've been unassailable) and is now trapped at the heart of Vetch's citadel. Nice Job, Haven.
Done double duty in Lunar Knights. Dumas was ruling over the planet using Casket Armor, the paraSOL, and bottlenecked humans all in an attempt to protect his own people from the paraSOL's Planet Eater functionality; Lucian and Aaron taking Dumas down gives Polidori a reason to fire it up. Furthermore, after taking down a simulacrum of Polidori at the very top of the Vambery, a freshly revived Dumas warns them that what they just did was akin to starting a war with the Immortals, an entire race of Omnicidal Maniacs. I want my sequel, Konami.
Played with in the Mega Man Zero series. In Zero 3, Zero forces Copy X to go "all out," but instead of activating his ultimate form, he instead activates a bomb that was planted in his body by Dr. Weil. Results: everyone thinks Zero retired Copy X and Dr. Weil takes over Neo Arcadia, as an even less benevolent ruler.
It got worse in Zero 4. Due to Weil becoming the ruler of Neo Arcadia, Craft decides that the only way to get rid of him is to blow up Neo Arcadia. Nice Job Killing Twenty Million Civilians Because You Let The Bad Guy Take Over, Zero.
Before that, there's Ciel, effectively the series' female lead, responsible for creating the Big Bad of Z1, the imperfect Copy-X.
Star Fox 64 uses this trope in one area. When you destroy the first 4 weak points of the Meteo boss, the rear laser cannon/shield breaks off... and flies straight at you.
The ultimate focus of Brave Fencer Musashi: you spend the game running around collecting the scrolls that the original Brave Fencer Musashi used to seal a dark wizard with the sword Lumina. You do this to power up the sword in the hopes of stopping Thirstquencher Empire's bid for world dominance, only to find out that the original Brave Fencer Musashi didn't seal the dark wizard with the sword, but in the sword, who was then released. Pat yourself on the back, Musashi, you earned it.
Well, in all fairness, Allucaneet Kingdom is the mostly at fault for this, due to not properly recording just how the last Brave Fencer sealed away the Dark Wizard. Saving the kingdom is one thing, but releasing a planet-ending threat is not a good trade-off.
Especially considering that Musashi never really had much interest in gathering the scrolls. If they'd just set him loose on the Empire itself, he probably would have curbstomped Flattski soon enough to avoid most of the woes that befell them during the game.
The final boss of the World of Warcraft dungeon "the Blood Furnace" is overseeing the efforts of the dungeon's fel orc residents to keep a powerful demon lord confined so they can suck his blood away. He attacks you, yelling that you're "ruining everything." When you kill him, his last words are: "Good luck... you'll need it." (Luckily, the demon is in his own separate instance beneath the floor grating.)
Also in Shadowmoon Valley — the quest chain that leads to the resurrection of Teron Gorefiend. Whups!
Also the Shadow Labyrinths — the cult you just killed there was fending off a Cosmic Horror (Murmur). Although, this time, you get a chance to kill it right then.
The entire Hakkar questline, starting in Tanaris and leading you around the world thrice and through three instances, has you resurrecting the blood god, revitalizing the evil troll empire, and finally re-defeating him with a raid.
The first campaign in Warcraft III's expansion set is even worse. The player takes control of a group of night elves on their quest to stop Illidan from using a powerful evil-looking artifact. It's only after you stop him and destroy the artifact that you find out he was trying to destroy the Lich King who controlled the undead.
Except that, as revealed in Wrath of the Lich King, merely killing the Lich King WOULDN'T end the undead threat once and for all; in fact, Ner'zhul was holding the undead in check, and his death would have made the undead an even greater threat.
Admittedly, Illidan's plan was to destroy Northrend in the process, an equal example of the hero breaking it.
To make Illidan's actions seem even less heroic, he was doing them at the behest of a greater evil, and destroying Northrend would have seen to the entire planet splitting open. Not as heroic as a lot of people initially think.
Illidan's dialog seems to indicate that he wasn't aware of the full damage the spell would cause. Illidan has a history of not thinking things through.
This far and nobody's brought up the best gem in the gameworld? "Upon further analysis of the Gnomeregan situation, it would appear as though we not only failed to eradicate the troggs but we also happened to turn most of the gnomish race into horrific, mindless, evil-doing leper gnomes..."
Drakuru plays you for a chump while locked in a cage, using you to take down the Drakkari Empire and clear out their stronghold.
Whereupon Drakuru calls up The Lich King to inform him of your success at restoring him to the place of power in Drak'Tharon, which in turn inspires the Lich King to transform Drakuru into one of the most powerful Death Knights in the scourge army. Hey, at least then he offers you a job as a reward for your help instead of killing you outright.
Apparently when we killed C'thun, we risked destroying the planet because the Old Gods tied their existence to the survival of Azeroth. And now we're going after another one, fully aware of this possibility.
Well Arthas, it seems trading your soul for power to get revenge and save your kingdom turned out to be less of an awesome idea than it seemed. Especially since Mal'Ganis didn't actually die.
Warcraft really likes this one. This one depends on whose side you think is the hero and who is the villain, but Daelin Proudmoore declaring war on the Horde? Not a great idea. Not only did you get yourself killed, you pissed off the Horde, and when they killed you that pissed off the Alliance because you were a war hero. Oddly enough, the leader most affected (his daughter) actually helped take him down and is still the one most devoted to peace.
This happens similarly with the controversial Alliance attack on Camp Taurajo. General Hawthorne attacked and sacked the Tauren village, a "soft" target that had value for the war effort, but allowed openings in his lines to allow some civilians to escape, but Horde players and characters contend that this was not enough, as there were civilian deaths. A Horde questline leads players to kill him, which leads the Alliance to launch an attack to avenge him. Either the General's attempt at mercy backfired, or the Horde, by killing the person who attacked him, opened themselves up to worse retaliation.
Most recently, by killing the corrupted Watcher Loken in the Halls of Lightning, the players accidentally set in motion a process to get the Titans to destroy and rebuild Azeroth. Oops.
In a It Seemed Like a Good Idea at the Time moment, in one quest chain in Burning Crusade, the players help Orcish leader Garrosh Hellscream get over his depression and grow to become a leader. And, in the next expansion, Wrath of the Lich King', he's a bloodthirsty maniac who's trying to restart the war with the Alliance and might be out to replace the Orcish Warchief, Thrall. And he's only in the position to do this because of the players' intervention.
As of Cataclysm, Thrall has been forced into stepping down as Warchief in order to commit himself fully to finding a way to keep Deathwing from wiping out Azeroth. No prizes for guessing who filled his position.
In the fourth expansion, Mists of Pandaria, Garrosh goes mad with power and become the expansion's Big Bad.
There are a number of quest lines that operate on this trope. Probably one of the earliest ones encountered belongs to the Night Elves. In your first few levels you encounter a satyr who just wants you to go kill a few animals and bring him back some of their bits and parts. After completing this quest, you get another quest after it's explained that you really kinda probably shouldn'ta done that because that satyr is really up to no good. So you wind up turning him into a frog. It's a very short quest line and isn't terribly fleshed out, but sets up a pattern for you being tricked into actions that result in rather negative consequences throughout the game. You just never learn, do you, Hero.
Good old hermit Abercrombie from a certain Duskwood quest chain. While it seems you're just doing simple favors for a kindly old man, you eventually find out you've helped him build a Level 35 Elite abomination named "Stitches" who runs along the main road towards Darkshire killing any low-level players in his path. Do the same quest with another character, making sure to read the quest text this time, and you'll see how obvious this outcome was.
The Horde quests in Tirisfal Glades and Hillsbrad revolve around making a plague supposedly to use against the Undead Scourge. It is later revealed in Northrend that this was not the case as the plague was unleashed on the living as well at Angrathar: The Wrath Gate.
In addition, a quest in Stonard has you putting together ingredients for a truth serum crafted by one of the Forsaken Apothecaries who's making this New Plague, so you can get information out of a captured human. Turns out the human wanted to give the orcs and other Horde leadership information on the Apothecaries' plan to create a new plague... and the truth serum you just fed him was actually just poison. Oops.
An early Dragonblight quest chain has you attacking outposts of the Blue Dragonflight, beating up their human sympathizers one by one and trying to figure out what they're doing with the local magical ley lines. On the body of one of their leaders (which one it is depends on your faction) you find a half-finished letter revealing that they in particular were threatened into slavery with their family's lives on the line, and that they were actually working to sabotage the operation — leading to an implicit assumption that at least a sizable portion of the task force in general could be doing the same.
The entire Wrath of the Lich King expansion is leading up to a massive, epic battle against the Lich King. When your raid group finally reaches the top of Icecrown Citadel and takes the Lich King down to 10% of his health, he instantly kills you all and claims the whole Argent Tournament and Icecrown Citadel instance was exactly what the Lich King wanted — pitting the strongest champions of Azeroth against one another and Arthas's strongest subordinates, so that only the cream of the fighting crop would come to face him in battle... so he can kill them all and raise them to be his new Scourge commanders. However, just when you think all is lost, Tirion Fordring breaks free of the ice block he's imprisoned in and shatters Frostmourne with the Ashbringer, releasing the contained souls, one of whom resurrects the raid, allowing you to finish off the Lich King. It turns around twice more, though, in the ending cutscene, when Terenas Menethil confirms what Uther said in the Halls of Reflection: Arthas's death means the Scourge will rampage out of control and cause even more of a threat to the living. But that too is averted when first Tirion, then finally Bolvar Fordragon resolve to make the Heroic Sacrifice of becoming the Lich King themselves to be the "jailor of the damned". And Bolvar even looks a bit like Tal Rasha.
This trope comes into play in the quest chain that opens the Molten Front, although you're an Unwitting Instigator of Doom instead of an Unwitting Pawn. Shortly before the attack begins, Hamuul asks you to investigate a Druid of the Flame nearby. The druid, Leyara, binds you with roots and badly burns Hamuul, forcing you to delay the attack until you have enough Marks of the World Tree.
For ten thousand years, Pandaria has been at peace save for the cyclical war against the mantid swarms. In Mists of Pandaria, the Horde and Alliance proceed to unleash the Sha and trigger at least five wars across the continent in the process. All without leaving the first area.
Chi-Ji: It seems the time has finally come to face the consequences of Shaohao's actions. This conflict has been a long time coming — the arrival of your people was merely a catalyst. Now, your help will be necessary if Pandaria is to survive.
When a few Sunreavers broke their neutrality and aided the Horde in a black op, Jaina went into a fury and imprisoned or killed every Sunreaver in Dalaran. Varian calls her out on this as it ruined his plans to sway the Blood Elves to his side.
In Starcraft, Zeratul is the first to permanently slay a cerebrate while Tassadar uses his forces to distract a Zerg contingent led by Kerrigan. However, Zeratul inadvertently creates a temporary psychic link with the Zerg Overmind. The link allows the Overmind to determine the location of the Protoss homeworld Aiur and invade. The Protoss never mention this fact however, so it's possible they didn't know how the Overmind located Aiur. Aldaris and the rest of the Conclave might have been even less pleased with the return of the Dark Templar if they had known that one of them was essentially responsible for the Zerg invasion.
Upon defeating the Wall of Flesh, the boss of the underworld in Terraria, you receive a message saying "The ancient spirits of light and dark have been released". Now, The Corruption will spread like wildfire through the game world, and the only thing that can hold it at bay is another biome filled with rainbows and unicorns that is just as infectious and with creatures that are just as dangerous. Nice job breaking it, player.
Dhaos, the Big Bad sorcerer from Tales of Phantasia, wages war against the world in general across several generations with the aim of taking a Mana Seed from the Tree of Life. It isn't revealed until after you've finally killed him that he was actually a being from another planet, on a mission to replace his world's own Tree of Life, which is dying. Oops. After everybody else is gone, though, the resident goddess transforms his body (and hers, too, depending on which version you play) into a Mana Seed and sends it on its merry way, making one wonder what the fuss was all about.
Midway through the game, a human army, desperate to fight off Dhaos, unleashes an enormous mana-sucking weapon which has the unintended (but totally predictable) effect of killing off our Tree of Life. It's a little uncertain whom the bigger "oops" is on here, since Dhaos' whole war was about preventing humanity from bleeding out all the mana with their excessive use of sorcery. Nice job on that one, eh?
The magitek cannon backfired on its second firing and destroyed a good portion of Midgards. Dhaos was sure that Lyzen wouldn't be a massive idiot and fire it before it was ready.
In Tales of Symphonia, the prequel, eventually reveals that the whole magitech problem which destroyed most of mankind in Phantasia's backstory, and comes close to doing it again during Phantasia, is the heroes' fault, as the Big Bad they killed was keeping technology stagnant for the purpose of preventing humans from making Mana Cannons and using up too much mana and causing mass destruction. Ironically, they use a mana cannon to defeat him, and it is implied that it was mana cannons' use which led to him taking over the world in the first place.
Why people keep using the damn cannons if the technology has over 8000 years of history of causing death, destruction, and suffering to all (including its users) is never addressed.
Tales of Symphonia is full of this. Your heroic quest to save the world by reviving the flow of mana turns out to actually be stealing the mana from a parallel universe, which explains why all these blue-haired elf freaks and ninjas are trying to kill you for it. Of course, when you are nearly finished in your quest, but haven't touched Disc 2 yet, you know something's up.
It's sort of subverted in that the party never goes through with the regeneration because of the Friend or Idol Decision that results from it.
On a more personal note, the Key Crest that Lloyd gives Colette to save her soul ironically nearly kills her because while it restores Colette to normal, she is slowly being poisoned and crystalized by her Cruxis Crystal, as it lacks a few critical touches. This leads to your first Disc 2 quest.
It even gets worse: having moved on to that parallel universe, the heroes proceed to blindly assume that cutting off the exchange of mana between the two universes will save both worlds and proceed to do so. Naturally, this nearly destroys both worlds instead. And you know that something's even more wrong when you've almost finished your second world-saving quest and STILL haven't touched Disc 2. Yes, you read that right.
In fact, this continues right on through the final battle in that killing the boss nearly destroys the world yet again, except that the requisite Final Cutscene Awesomeness allows the hero to finally go about saving the world.
Technically that's more Nice Job Not Fixing It Completely Hero, since the final boss was planning on taking Derris-Kharlan away with the Great Seed and leaving the world to die. Their only mistake was believing that defeating him was all they needed to do to save the world, when it was only the first step.
In the first part of the game, Genis' visiting Marble at the human ranch is seen as a violation of the non-aggression treaty when Lloyd gets caught on camera killing the guards that saw him, enabling the Desians to attack the village. To make matters worse, Marble is turned into a monster, and sacrifices herself to stop Forcystus.
And Nice Job Breaking It, Renegades, for taking an eternity of slapfighting back and forth before they informed their "enemy" that THEY WERE ON THE SAME SIDE.
It could also be argued that the entire game is a severe case of this, what with Mithos the Hero who saved the world by breaking it being the Big Bad.
Even the sidequests aren't immune to this. One sidequest has the heroes dealing with a family who lost a child when the giant tree went berserk. In fact, that was the same incident that also killed Marta's mom. Nice job ruining people's lives, heroes. Another example has the heroes helping Abyssion lift his curse by looking for the Devil Arms and having Abyssion dispose of them. Turns out that Abyssion actually had you bringing the Devil Arms to him so that he can use them to gain ultimate power. Nice job unlocking the hardest boss in the game, heroes.
In the sequel, reuniting the two worlds in the first game has the effect of the major kingdoms about to declare war on each other.
Averted in the sequel by meaningful relationship development, because if Emil/Ratatosk had fully won the game, it would have ended with the world being overrun by demons. But there is a Heel-Face Turn which neatly averts the trope.
Played for tragedy twice with poor Ninian. First, the gang finds her adrift at sea with memory loss and takes her to Dread Isle... which happens to be right where Nergal wants her. He forces her to summon a dragon which ultimately ends in the death of the man they were trying to save, oh shit! Later, Eliwood goes through a cave full of lava patches to get the legendary Durandal, a sword that kills dragons. It lives up to its reputation just moments after they leave the cave... wait, you mean that dragon was Ninian?! NOOOOOOOOOOOOOO!! You really should have planned things better, heroes.
And then there's this little kicker. If you, as the game's tactician, did exceedingly well when you finish the game (A-S rank), your legacy causes Bern and Etruria to go war because they desired your skilled mind so much. That's right, that S-Rank Hector Hard Mode you spent weeks over caused two of the most powerful military nations to go to war over you.
Eliwood and Hector do this by rescuing Prince Zephiel from being assassinated under his father's orders. Guess who comes back to invade in Fire Emblem 6?
Early in Phoenix Wright: Ace Attorney: Trials and Tribulations, Phoenix proves his client innocent of theft... with an alibi which implicates him as a murderer. Whoops.
In Phoenix Wright: Ace Attorney: Justice For All in the last trial, Phoenix's work in clearing Matt Engarde of his charges very nearly implicates a completely innocent witness in the crime, to the point where it takes a confession from Engarde himself to actually prove who was the real murderer. This all happened because Phoenix had no other option than to stall for time though, as the assassin who Engarde used to commit the crime had kidnapped Maya to ensure Phoenix would cooperate and get Engarde free.
In Phoenix Wright: Ace Attorney case 5, the same detective was apparently stabbed to death in both the prosecutions building and the detective's prescient at the exact same time. Phoenix works his ass off finding fingerprints, getting info, and cross-examining people as well as pointing out contradictions in a video tape in order to prove that the murder that took place in the precinct was not an actual murder, which he does... this, however, proves that the murder took place in the prosecutor's building and therefore the only person who could have killed the victim was his client... good job there Phoenix!
The inside of the cave is a shambles after the unavoidable fighting in scenario 29 of the Earth Route in Shin Super Robot Wars. Prof. Eri Anzai nearly faints, totally unable to comprehend how the hotheaded Domon and Ryusei could ignore the cultural value of whatever was in that cave.
In Super Robot Wars UX, ALL of the aliens respond to Denton's message which include the Festum, Vajra, ELS, Human-Machina, Skrugg, and Anticross. In Heroman finale, it's shown that that's not the case: the Skrugg were called to the wrong Earth by the same message which called the main cast.
In Treasure of the Rudra, during Sion's Scenario he is stuck on the Sky Islands and wants to return to Terra Firma to stop the Rudra Cult. However when he does activate the path back to Terra Firma, the entire archipelago falls, putting everyone at risk of being killed by the Rudra.
Said Archipelago was part of the Earth in the past anyway.
In Castlevania: Curse of Darkness, Hector's defeat of Dullahan turns out to be a vital step in Isaac's plan to resurrect Dracula a century early. ...Well, Isaac's plan as likely dictated into his brains by the lurking spirit of Drac Himself. Lampshaded:
Isaac: You've resurrected the castle! *slow clap* Hector, bravo!
Two of the four possible endings of Castlevania: Symphony of the Night involve an underinformed Alucard eliminating the Belmont bloodline by beating the stuffing out of one extremely possessed Richter. Seeing as the Belmonts are humanity's best and perhaps only hope in the fight against Alucard's infamous father... Oops.
In Castlevania: Portrait of Ruin's true ending path, it's revealed that Brauner was the only thing preventing Dracula from being resurrected. After the players defeat him, he has a moment of clarity, explains his backstory about losing his daughters in World War II, then is promptly finished off by Death, who cackles, resurrects Dracula, and then forces you to FIGHT BOTH OF THEM AT THE SAME FUCKING TIME.
It goes back even earlier than that: Death was initially only lurking around Castlevania because that's what he does. He had no idea anything was skew-wiff until Charlotte spelled it out for him. Hence, Brauner's death when he was close to redemption, and Dracula's resurrection when he was previously still sealed and only being tapped for a power source, are directly Charlotte's fault.
Castlevania: Order of Ecclesia does this too, doubling as a Nonstandard Game Over: if the player hasn't rescued all of the villagers before defeating Albus, Shanoa completes the Dominus glyphs and uses them on Dracula's seal, only to unwittingly kill herself and RELEASE Dracula, rather than destroy him. Whoops.
In Kirby's Adventure and the remake Nightmare in Dreamland, Kirby defeats King Dedede and his henchmen, repairs the Star Rod, and puts it in its rightful place on the Fountain of Dreams... where it gives the Nightmare hiding in the fountain the strength to emerge, and Kirby has to beat that, too. Oops.
And in the true ending of Kirby Squeak Squad, in his quest to recover his cake from the titular thieving band of mice, he defeats every villain in his path, recovers all of their stolen treasures, and opens a sealed door in his path. In front of him is what seems to be the last of their chests, the one that must contain his cake. Oops, turns out it's not one of their chests at all, but a coincidentally identical prison for an ancient evil. This decision becomes even less intelligent by the fact that he continued to chase THAT PARTICULAR CHEST thinking there was cake in it even after Meta Knight stole it from him just before he could open it. After all, Meta Knight just LOVES stealing strawberry shortcakes from people.
In Kirby Super Star, Kirby goes out to awaken NOVA, a mysterious cosmic clockwork entity, so that he can wish for the Sun and Moon to stop fighting. Then Marx knocks him aside. Turns out he had you wake Nova up so he could use it to conquer Popstar. Crap. Then again, the Sun and Moon stop fighting so they can hold Nova off...
In Star Ocean: The Second Story, your team investigates the Eluria Tower to find out about the demons that are attacking all the towns. Too bad that you accidentally bring the key to the "Sorcery Globe" with you. The result? Instead of the planet Expel being destroyed centuries from now, it gets destroyed immediately. Whoops.
After you save at the final save point before Indalecio, do not initiate the Private Action with Filia unless you want to fight an Unstoppable Rage version of Indalecio that forces you to trap him. If you don't, he'll slaughter you.
Subverted in the final battle of Eternal Darkness. The player has to use the Villain's giant Circle of Power (which he had used to unseal his Canned Evil, Big Bad Elder God) to summon the Canned Evil God that trumps him/her/them/it, stalling the first one and letting the heroine deal with the villain himself. Upon offing him, she realizes that the god she had summoned is just as Big, just as Bad, and just as in need of resealing, at which point the grandfather (also controlled by the player at this point) finishes the job.
...Then possibly un-subverted with the 100% ending. Playing the game 3 times, destroying the 3 different gods, was just a Batman Gambit by the 4th god so that he could destroy the gods he was supposed to prevent from running rampant, in order to enact some kind of plot. He's already been condemned to a slow, agonizing death, and it's not made clear whether the plot is actually something bad from the ending, so it's unclear if it's returned to being played straight or not.
Enchanted Arms takes the "Way to Go, Serge" rule and runs with it. You're being manipulated to do exactly what the Big Bad wants you to up until the VERY last part of the very last boss fight. Destroying the evil creatures that were killing everybody was exactly the WRONG thing to do. And this isn't even a spoiler because the game itself spells it out for you — constantly, from pretty much the very start. You're just not able to do anything about it. Do be fair, Atsuma is an Idiot Hero of quite high degree. In fact, in one part you're given the option of saying the thief is small, light, and nimble, or that he/she trains mice. No joke.
In Mario & Luigi: Superstar Saga, Lady Lima demands that the Mario Brothers prove their identity by repairing the castle's plumbing. That was actually Cackletta in disguise, and the broken sewer system was the only thing keeping her from getting into the Beanstar chamber. Nice job fixing it, hero.
In the sequel, Mario & Luigi: Partners in Time, the titular brothers and their infant companions gather up the pieces of the Cobalt Star, only to realize that the star is actually a broken prison for the Big Bad. Averted earlier in the game. The brothers rescue Princess Peach, only for Bowser to kidnap her again, prompting the brothers and babies to go after her again. Then it turns out that the Peach the brothers rescued, Bowser kidnapped, and the brothers rescued again was Princess Shroob in disguise.
And all those special moves and powers the Bros. helped Bowser obtain in Bowser's Inside Story? In Dream Team, he still knows all of them, and is more than happy to use them against Mario and Luigi. Whoops.
Also used in Paper Mario: The Thousand-Year Door, by way of becoming the Macguffin Delivery Service. The Crystal Stars are the key to unlocking the Thousand-Year Door... and Mario ends up bringing all seven to the door after being told that it had opened on its own due to the thousand-year cycle having passed. It hadn't, and as soon as they find this out, the ally that told them otherwise was revealed to be Doopliss in disguise and the villains come out and open the door. Nice one. (The Xanatos Gambit was that the last Star was already in the villains' possession, and they would get the Crystal Stars regardless of who won the battle.)
After Mario defeats Count Bleck in Super Paper Mario, it's revealed that Dimentio was using everyone as Unwitting Pawns in his own grab for the Chaos Heart, which is in the process of destroying the multiverse. After taking advantage of the Count's defeat to take it for himself, he manages to speed up the process, destroying all dimensions in the process. Oops.
Warhammer 40,000: Dawn of War ends with Brother-Captain Gabriel Angelos destroying an artifact containing a demon... which, instead of destroying the demon with it, let the demon go. The demon merrily thanks Gabe for his help.
From his words, it seems that he destroyed the artifact knowing it, so he could destroy the demon completely later.
Apparently he wasn't in a hurry to do that, because the demon managed to corrupt the chapter master, plunge the whole sub-sector into meatgrinder and (in all but one campaign) murder Angelos himself before being killed by some other guy.
In Warhammer 40,000: Space Marine, Captain Titus and his 2 comrades helped Drogan activate the experimental weapon Psychic Scourge, in hopes of turning the tide of war against the Orcs. However, the weapon ended up opening the warp gate for the forces of Chaos to pass through, creating even more havoc for humanity.
In Star Control 2, the Shofixti blew up their own star to take down a massive Ur-Quan fleet. That's great and all, considering they've been enslaving everyone up until that point. That is, until you find out that the Ur-Quan's genocidal cousins are coming to this section of the galaxy, and the Shofixti had crippled the enslaving Ur-Quan's fleet enough so that they'll lose the upcoming doctrinal conflict.
What you need is a scroll of Protection From Magic and some kind of insanely powerful weapon, like Crom Faer or Carsomyr.
And this pales in comparison to releasing Demogorgon, the most powerful Demon Prince in the universe. And somehow, even that isn't as bad as defeating him. "Killing" a demon in the mortal realm merely banishes it back to the Abyss for a hundred years. That's right, all you did was give Demogorgon a ticket back home.
Not as devastating as you think because the hundred year banishment simply blocks them unless the one to defeat the demon wills it back. After the banishment ends the demon still needs to be summoned and anyone with that level of power is usually not inclined to summon a world destroying demon they can't control.
Another BioWare example, but the "heroes" are pretty arguable. In Jade Empire, the Brothers Sun save their empire from a crippling drought by enslaving the deity in charge of rain and slaughtering her followers. Unfortunately, said deity and followers were also in charge of shepherding the dead to their rest and reincarnation, essentially damning the Empire to a slower, nastier death... and leading the middle brother onto one hell of a plan to try and force order back onto creation.
To get across just how bad this is: by defeating Lynx at Fort Dragonia, Serge wounded him, at which point he swapped bodies with Serge, leaving Serge in a weakened form. The player then goes through hours and hours of Humans Are the Real Monsters philosophizing in order to destroy FATE, at which point he discovers that FATE was the only thing preventing the Dragonians coming back and erasing humanity from existence. That's right, the solution to the firstNice Job Breaking It, Hero is anotherNice Job Breaking It, Hero.
It gets worse. It turns out the Dragon God is (more or less) an extension of the Time Devourer, and defeating it hasn't fixed anything. Moreover, trying to kill the Time Devourer will just result in another NJBIH, thanks to its nature.
...and yet, the whole damn thing is implied to by a Gambit Roulette by a minor character from the original game to actually save all of existence. From what, the game isn't clear, but it does try to explain that all of this actually had a point somewhere. The fact the ending implies a Reset Button was smacked to stop all of this crap from happening either justifies this or makes it all the more frustrating for the player.
In StarCraft after you help Arcturus Mengsk overthrow the Confederacy, he crowns himself the emperor of Terran space and becomes just as bad as they were.
Preventing this becomes one of the major plot points of SC 2, after it is revealed that the heroes must not kill the Big Bad Kerrigan, as she's ostensibly the only one who can stop the Bigger Bad from annihilating all life in the galaxy, like he does in the Bad Future.
In Samurai Warriors 2, in Saika Magoichi's story it's revealed that the bandit attacks are caused by Nobunaga's assassination (at Magoichi's hands), since he had kept order (and presumably bandit suppression) up while alive. Sure, Nobunaga massacred Magoichi's village for his unit being so dangerous, but...
In Metal Gear Solid, when you finally insert the last keycard (after changing the shape of the card three times using different temperatures) into the last terminal in order to disarm Metal Gear REX, you actually end up ARMING the machine. Nice job, Snake. But it's not all bad, because then you get to destroy itmanually (plus, the only reason he armed it was because of misinformation that was implied to have even most of his support staff fooled). In the fourth game, destroying the Patriots AI system would also cause intense PTSD in every soldier in the world, thanks to the SOP system suppressing emotions, and damage basically every electronic service or infrastructure in the world. Sunny's FOXALIVE computer virus averts this trope narrowly.
Many of the other negative effects are avoided, but the PTSD is directly stated to have occurred. It is blatantly demonstrated in the FROGs.
Plus, Drebin implies afterwards that in addition to the aforementioned PTSD, most of the world ended up completely bankrupt and having to pay a monetary debt for PMC usage that was so huge that not even PMC regulation laws would be enough to get them out of the debt anytime soon, and that the outcome is either that the UN taking over what's left of the planet would result in an unofficial neo-Patriots group rising, or that the world still will end up going into a war apocalypse anyway.
In the first and second game, Solid Snake's actions in regards to destroying Metal Gear resulted in a mushroom cloud as well as an earthquake in the aftermath of the explosion in the Galzburg region of South Africa are considered this. Even moreso when, according to Kyle Schneider, the aforementioned mushroom cloud was actually from NATO's air raid bombing of Outer Heaven that resulted from Snake destroying Metal Gear, and not its self destruct device going off, highly qualify as a Nice Job Breaking It, Hero moment. The fact that he also killed Big Boss in Metal Gear 2 as well as severely wounded Gray Fox to the point that he ended up experiment, resulting in him being targeted by a governmental bioweapon by Gray Fox's vengeful adoptive sister also qualifies as well.
Midway through the game, the hero and Curly attack a huge spherical creature and nearly destroy it. Said creature is the core that keeps the floating island in the sky. A last-second save of the core by Misery and the Doctor keep this NJBIH moment from coming full circle.
Later, after defeating the evil Doctor who had subjugated the floating island and its inhabitants as bearer of the Crown, the hero discovers he has merely freed him from his corporeal form, allowing him to use the full power of the Red Crystal, and possess and corrupt his friends, and the island's core. Cue the real final battle with the Doctor.
Defeating the Doctor at this point means destroying the core for good — if you flee the sinking island at this point, then the end cutscene gives several slow pans over areas of the island, and all the people still inside, before the island crashes, killing everyone inside. Way to go. But if you completed the right sidequests by this point, then you can enter the Brutal Bonus Level and fight the True Final Boss — defeating him will save the island from destruction.
In the finale of Diablo, the hero takes the soulstone containing Diablo's spirit of pure evil and jams it into his own forehead, intending to contain the spirit within him. He fails spectacularly as Diablo consumes his soul, takes over his body, ravages the town of Tristram that the hero spent all of Diablo trying to save, and becomes the villain of Diablo II.
Also, Tyrael destroys the Worldstone in the final cinematic after it's corrupted by Baal. He does realise this may make matters worse. Diablo III, anyone?
Even before D3 has been released, one effect of the Worldstone's destruction is known, from the map on the D3 website. The Arreat Summit, tallest mountain in the world, container of the Worldstone, as well as all the people who live there, has been renamed the Arreat Crater.
And that's not even Tyrael's first screw-up. Using the soulstones bound the Prime Evils, sealing them away... and making it possible for them to escape pretty easily a few centuries later. Who gave him the idea? Izual, an angel tainted by Diablo.
The hero of Diablo III is duped into putting the souls of all seven of the Great Evils into a special Soulstone — so that Adria, the one who sent you on this quest, can use the stone to bring about the rebirth of her master Diablo, using the body of her own daughter Leah, who it turns out she had with the Dark Wanderer, a.k.a. the Diablo-possessed Warrior mentioned earlier. Oh, and because of all seven Evils being in that stone? Diablo has become the Prime Evil, essentially a God of Evil reborn. Who then proceeds to mount an invasion of the High Heavens, with even the most powerful of the angels not having a prayer in Hell or Heaven of stopping him.
Essentially, the entire series can be summed up as people being handed two equally terrible options to resolve a situation, and having to decide, usually under the pressure of the imminent end of all creation, which option will suck the least. In the first game, had Aidan not attempted to contain the soulstone at all, Diablo would just broken out on his own and started the whole process over again anyway. Had Tyrael not shattered the corrupted Worldstone, demons would have corrupted all of humanity without any recourse. Had the nephalem hero not attempted to contain Azmodan and Belial, they would have stomped all over humanity with their unchecked armies. Reaper of Souls continues this tradition of crappy choices made in the face of the end of all life with the nephalem hero not being able to stop Malthael from shattering the black soulstone and thus being stuck with the choice of either killing him and thus releasing all of the demon lords all over again, or not killing him and letting him wipe out all life in Sanctuary. The hero chooses the former and is now directly responsible for releasing Diablo again. Sucks to be the hero of a Crapsack World, doesn't it?
In Call of Duty 4, the United States sends in a Marine expeditionary force to dethrone Al-Asad, the dictator of Qurac. They succeed, easily steamrolling over Al-Asad's army, but his defeat only results in him detonating a nuclear bomb in his own capital, destroying a good-sized chunk of the country, along with most of the U.S. expeditionary force (including the player character).
This is justified for two very good reasons: 1) The U.S. expeditionary force does steamroll over Al-Asad's army easily, and it can be assumed they would have controlled the capital in a matter of hours after the initial invasion, gaining control of the nuke at the same time (given the Shock and Awe nature of the attack, this was most likely the objective), and 2) who's crazy enough to set off a nuclear bomb in their home turf, killing themselves in the process? Generals planning the attack probably assumed that Al-Asad had some sanity. They were, unfortunately, wrong.
Al-Asad was never in the city when the nuke went off. That's the whole point of the Safehouse mission. He is, according to the informant Nikolai, a coward.
Also, in Modern Warfare 2, much of the action is driven by the Ultranationalists, under the command of Big Bad Vladimir Makarov. According to dialogue, Imran Zakhaev kept Makarov 'in check'. Guess who you killed at the end of the first Modern Warfare? Nice job, Soap.
Not to mention how the entirety of Task Force 141, the Ranger (Pvt. James Ramirez and his squad) you play as, and pretty much the entire American military are being manipulated by one General Shepherd, who's planning to use the conflict to turn America into heroes and obtain the biggest military force in history.
Also, a particularly chilling example in Modern Warfare 2's opening mission, "No Russian". CIA Operative PFC Joseph Allen is inserted into Makarov's terrorist cell under the guise of a Russian named Alexei Borodin. He's then ordered to slaughter an airport full of innocent civilians in order to prove his loyalty to Makarov. At the end of the mission, Makarov shoots him in the head unexpectedly, revealing that he knew Allen was a spy all along. He leaves the body there for security forces to discover, essentially framing America for the terrorist attack. The entire mission pretty much leaves you with a sick feeling in your stomach — not only because you killed innocent civilians by the hundreds, but nothing came of it and you saved no lives in the long run. In fact, you pretty much helped start World War 3 in the process. Nice job breaking it hero, indeed.
About 3/4ths of the way through BioShock, the hero comes upon President Evil antagonist Andrew Ryan, whose death you've been seeking for the entirety of the game. The hero is all set to kill him, but that's only right before Ryan gives him a horrifying Hannibal Lecture masterfully combined with a "The Reason You Suck" Speech, revealing that the hero is only a mind-controlled pawn whose actions are only going to hand control of the city over to the Big Bad. Nice job, hero. It gets better: Andrew Ryan serenely hands you a golf club, and orders you to kill him with it, so he can simultaneously deny the Big Bad the pleasure of killing him and humiliate the hero while dying on his own terms in a Crowning Moment Of Awesome.Better to Die than Be Killed.
It's more than that. President EvilAndrew Ryan WAS trying to kill the protagonist, and he knew that Jack was his biological son but didn't care. The Thanatos Gambit plot of the Big Bad aside, if the protagonist didn't kill the President Evil, he would not have made it out of Rapture alive.
In The World Ends with You, you're given a mission early in the game to make a certain pin popular. In the end, that turns out to be the key to Kitaniji's plans for Instrumentality. And since you have to complete the missions or face erasure, you had no say in whether or not to do it.
It gets worse. Once you defeat Kitaniji, you learn that he and Joshua were playing a game. The prize was Shibuya. If Kitaniji couldn't pull off his Instrumentality in one month, Joshua would erase it entirely. And guess what you just messed up? Thank heavens for the Gainax Ending, huh?
In the Halo series, when one of the Halo weapons is activated, and then deactivated prior to firing, it causes all other Halos in the galaxy to go active and on standby, whereupon a single command from the Ark command center will fire them all, effectively ending all life in the known universe. Whoops, indeed.
In Halo 2, as the Arbiter, you are sent to kill a "traitor" who has, in fact, seen that what the prophets seek is, indeed, the triggering of the Halo rings and the destruction of all life.
And then later in the game, capturing Sgt. Johnson and Commander Keyes, since only Humans can activate the Rings, thus giving the Covenant exactly what they needed to trigger the Halo rings and cause the destruction of all life.
Master Chief almost has his own Nice Job Breaking It, Hero moment in the first game — helping 343 Guilty Spark retrieve the Index and prep Halo 04 for firing, assuming it would kill the Flood rather than everything else. Luckily, Cortana is on hand to stop the process and clue the Chief in.
The novel Cryptum reveals that the Flood originated when humanity's ancient, more advanced predecessors found automated supply ships full of an unknown powder, which turned out to be genetic material. They injected this genetic material into their domestic animals, including a species called the Pheru, and it seemed harmless. A few generations later, the Flood as we know them started to appear. And since humans ate Pheru, they were infected as well. Attempts to contain the Flood bought them into contact with the Forerunner, who smacked them down back to the pre-tech level humans think they started at. And, it's implied they destroyed all knowledge of the Flood cure they had developed just to spit in the eye of the Forerunner. The Flood proceed to nearly destroy the galaxy.
In the Kilo Five novels, ONI has been forming dissent among the Elites to ensure that the Elites won't be a threat to the UNSC. But their actions have resulted in creating more forces who will join the Storm Covenant in fulfilling the Diadact's goal in eradicating humanity.
In the first System Shock, SHODAN's ethical constraints were removed by the player character. Whoops. It gets better too. In the second game, you find out the fate of the virus-infested grove that the Hacker jettisoned in the first game, where SHODAN was developing an experimental mutagen. Upon crash landing on Tau Ceti V, the mutants evolved into the collective alien hive mind known as The Many, the main antagonists in the second game. Additionally, ejecting the grove also allowed a portion of SHODAN's AI to survive. This version of SHODAN nearly succeeded in using the ship's warp drive to assimilate reality into cyberspace, after the player character spent a great deal of effort helping her gain control of it. Whoops indeed.
And in the second game, you help SHODAN against The Many in an Enemy Mine... Only to discover too late that The Many were the gray in the game's Black and Gray Morality, not the black you were led to believe... and with their lesser evil gone, there's no longer anything stopping SHODAN from conquering the universe. Whoops, again.
The gardens in the first game aren't really an example of this trope, though (since as dangerous as they were jettisoned randomly off into space, they were much much more dangerous orbiting around earth). That's less an example of 'nice job breaking it, hero' and more 'nice job notfixing it completely, hero'.
Another example that also results in a Nonstandard Game Over is, early in the first game, it's possible to activate the mining laser, which you need to do to blow it up. Except, you know, without getting it ready to blow up in the first place. Well, you've just helped SHODAN raze the Earth of life. Nice job breaking it, Hero.
In Shantae, suddenly, a genie, which were supposed to leave the earth, leaving behind only their half-breed kids like you, who looks like the game's villain sans pirate hat and suggests you cut your hair, which is your only means of offense, sends you into a dungeon to get the last MacGuffin, which the villain is hunting to power a tank to make herself ruler of the world, but leaves you to go in alone, despite the fact that genies have great power. When you show her what you have received, she puts on the pirate hat and laughs. Suddenly, you see yourself on the ground, MacGuffinless, as she runs away.
After you complete the last quest in Kingdom of Loathing, the council informs you that the monster attacks are due to your presence in the kingdom. They just really don't like you. And since you're stuck in a cycle of eternal ascension and reincarnation, the monsters will never go away.
On the other hand, the Council's offhanded way of 'researching' the 'problem', and the fact that they weren't in any rush at all for the Naughty Sourceress to be defeated (they pretty much tell you they love being in power) could mean that this was a complete lie to make you reset the continuity and bring them back into power. (See WMG)
After the first level of Star WarsKnights of the Old Republic II: The Sith Lords, namely Peragus (an asteroid-based fuel mining facility), the asteroid blows up, and, with it, an important and abundant fuel source is completely destroyed. Although the player had to get the place blown up (or blow the place up yourself, if you want to Kick the Dog) to stop the Sith, the player will be berated by damn near everybody for creating a galactic energy crisis throughout the first half or so of the game.
She's not really a Sith. Well, maybe she is. Who the hell knows? But the game doesn't depict the death of the Jedi as a bad thing; the Exile's crew members go on to build a new order that isn't as corrupt as the old one was (until the movie era, but whatever). The dark side version is really a better example; the player kills the Jedi — which arguably is a good thing — but because they fell to the dark side to do it, they've unwittingly caused a chain of events that will lead to the DEATH OF ALL LIFE IN THE UNIVERSE. But of course the Exile is forced to undo the damage, leading to more or less the same conclusion as the light side version: Jedi and Sith dead, with the Exile and company left to rebuild.
On a much smaller end of the scale, you can at one point give money to a beggar. If you do so, Kreia berates you for your naivety, and shows you a vision of the poor guy getting mugged. Of course, if you don't give him the money, he goes out and mugs some other poor guy, so there's really no way to not break things.
Back on the larger scale, way back when, the Exile destroyed Malachor in order to stop the Mandalorians. But all the deaths there lead to the events of both games, and the death of all the Jedi. That's why Vrook's such a Jerk Ass. Mostly.
Arguably the entire ending is this, since all the player manages to do is preserve a cycle of brutal, wasteful war between two ancient religious orders with childishly simplistic moral codes who are both pawns of the same self-destructive or just plain dickish cosmic force.
And the conga line continues on Star Wars: The Old Republic. Y'see, giving the Outcasts the map to their Promised Land was the canonical Light Side option. All Revan (you) did was condemn them to a slow death being picked off by disease, starvation, and rakghouls, then finished off by toxic waste.
The second (and much more epic) Nice Job Breaking It. Republic players get a flashpoint where they break Revan out of an And I Must Scream magical prison. What does our newly liberated "ally" do? Cook up an army of KillerRobots that will hunt down and kill anyone with even the slightest trace of Sith Ancestry. This equates to about 97% of the Sith Empire's citizens and probably several trillion Republic citizens, such as companion characters Kira and Sgt. Dorne. So much for maxing out your Karma Meter in the first game. It's BioWare - No Good Deed Goes Unpunished.
And for Imperial players: on Belsavis, the player character rescues the Dread Masters, thinking they'll help turn the tide of the war. Then they betray the Empire and become the Big Bads of the endgame (for both factions).
Time Hollow for the DS. Expect everything you alter in time to have at least one catastrophic side effect. Best summed up in the second chapter, where you take your friend's bike lock key to keep them from getting hit by a truck later that night. It hits a little boy and his dog instead.
But it's never permanent. Just as the first problem was fixable, the new one that cropped up is as well, until it reaches a point where everything is finally stabilized. That was one of the best things about the game (and the whole concept of the Hollow Pen), that it acknowledged that all actions have consequences and there are very few simple solutions, but no hole is ever too deep. I mean, c'mon, if all you had to do was prevent what started the whole mess in the first place, the game would be over in two minutes! I know that because you actually get a chance to do that. Finish a normal game, start a new one, and go outside and meet up with your bitter foe, then let him know that you're onto him and convince him to give you a little time (real easy). The rest is, as they say, strictly boilerplate. You even get a special ending.
SoulCalibur IV borders on this in Siegfried's ending — destroying the evil weapon which corrupted his soul, he creates a 'utopia'...but it's unclear if he knew this would mean turning the entire world into crystal, wiping out all life. Nice going there, Siegfried.
Tales of Vesperia plays with this, actually, in that invoking the trope is entirely optional (thus, yes, Stupidity IsNotthe Only Option). When the party collects the first Fell Arm in an optional sidequest, they decide to collect the rest (as is Franchise/}Tales tradition) in order to keep the dangerous weapons from falling into the wrong hands. Those wrong hands? The final boss, who, if you collect all of them, absorbs their power and gains an extra form that is seventeen levels higher and that much more difficult. And yes, once the sidequest is complete, it is necessary to beat him to finish the game and watch the ending. Nice job breaking it, player.
It's also played straight when Estelle uses her healing artes on Belius, which unexpectedly drives her insane, forcing the party to put her down and raising tensions among the major guilds, enough for many more people to die undeserved deaths.
And then there's another variation with Alexei, whose plan to obtain enough power to rule the world accidentally releases the Sealed Evil in a Can capable of eating the entire world, the Adephagos. Nice job breaking it, villain.
In the background for City of Heroes, Back Alley Brawler took his superhuman war on drugs all the way to South America and Afghanistan, using superheroes to raid drug cartels and burn poppy and coca fields directly to stop the flow of drugs into American cities. Unfortunately, the Evil Power Vacuum was filled with a Psycho Serum called Superadyne, and government research into that led indirectly to the Alien Invasion. Oops.
In the PS2 game Vexx, you start off the game being told by an old man called Darby to collect Wraithearts to power the Rift to travel to new worlds. After you collect a certain number of hearts, it's revealed that Darby is actually the Big Bad, Dark Yabu, in disguise, and had Vexx collecting Wraithearts for him so HE could use the Rift and unleash his pet Shadowraiths on all the worlds. Your objective remains the same, however.
Pretty much everything the party does for the whole game is an example of breaking something and desperately trying to fix it. The death toll they rack up far exceeds that caused by the villains.
Only because they stop the villains from committing genocide.
Star Wars: The Force Unleashed. First invoked when Starkiller, having rounded up discontents within the Empire and founding the Rebel Alliance, is suddenly attacked at the first meeting of said Alliance by his own master, Darth Vader, who reveals the whole plan to form the Alliance was a Xanatos Gambit by him and the Emperor to weed out their last remaining foes. Canonically, this is then inverted when Starkiller, or Galen by now, valiantly sacrifices himself against the Emperor to buy time for the Alliance leaders to escape... thus providing the Alliance with a martyr to rally around, inspiring them. The Emperor and Vader realize this... which means that, yes, the entire original trilogy was a direct result of a failed Xanatos Gambit by the Big Bad! Nice Job Fixing It, Villain!
Fallout 2. In a random time-travel incident, you go back in time to Vault 13. The only thing you can do is look at the Vault's Water Chip. And break it. Nice job!
The spinoff Fallout Tactics has every enemy faction's leader bemoaning that your aggression is dooming everyone, that you can't possibly stop the Menace from the West. Not that they explain what it is, or refrain from opening fire on you just the same.
How about the "Tenpenny Tower" quest of Fallout 3? Some ghouls, victims of Fantastic Racism, are trying to move into a luxurious tower, but the humans living there will have none of it. If you don't feel like slaughtering either party, you can convince the prominent members of the human community to either relent or move somewhere else, thus letting ghoul and human live together in harmony. Come back a few days later, and the ghouls have executed all the humans over a "misunderstanding."
It becomes even more ridiculous when if you kill the ghouls afterwards you lose Karma. Losing karma especially with the leader that practically gloated over the fact that all the humans had died horribly seems to be a bit much...
Actually, if you shoot said leader in the head the instant the ghouls start moving in, you avoid the slaughter of the humans. Still Black and Gray Morality, but it becomes a case of 'murder one guy to spare dozens' instead of 'tolerance leads only to death'.
You can also kill the leader of the ghouls and two of his followers (this completes the quest) without incurring a karma hit if you basically taunt them into attacking you first ("Anything you want to say before you meet your maker?"). You basically take an extremely unorthodox path to a best-of-both-worlds ending: [[spoiler Gustavo and everyone in Tenpenny Tower love you, jerks and otherwise "bigots" as they are, and they're indeed no longer in any danger. It's a shame that most of the truly nice ghouls are all the way on the other side of the game map.]]
In Fallout: New Vegas's Lonesome Road add-on, the Courier finds out that they accidentally set off the nukes in the Divide that turned it into a Death World. To proceed with the quest requires you to launch another missile that rains down more nuclear havoc on the region.
In the quest "Come Fly With Me", you can sabotage the Bright Follower's rockets so that they crash. However, as told in the epilogue note, the crash contaminates Novac with radioactive fuel, rendering it uninhabitable.
The hardest ending to get in Demon's Crest involves Firebrand taking on the usurper king Phalanx before getting all the crests. The resulting abbreviated boss fight (Phalanx doesn't get to transform) satisfies Firebrand's desire for revenge, and he takes off. But then we learn that "With the defeat of Phalanx, the Demon Realm lost all order and fell into anarchy. Many now ask if living under the rule of Phalanx would have been worse than the hell they are now confined to..."
Exmortis 2 has you free the Earth from the reign of the Exmortis horde... only for their leader, who set you up for this mission to begin with, to take their place as ruler. And, to rub it in, he says this:
Lord Vlaew: So, Mr Hannay, for your role in this, I commend you. For your part in this, I applaud you. And, for your help in this, I offer you a gift... (Suddenly, you're face to face with Vlaew, and the screen goes black. A scream echoes from nowhere.) Lord Vlaew: A quick death.
Odin Sphere is the story of five different heroes who completely and royally screw everything up. Cornelius escapes the netherworld and allows the evil and completely batshit insane undead King Valentine, who plans to bring about the end of the world, to escape with him. Gwendolyn rescues her husband from the Queen of the Dead, and by killing her sets free an insane, nearly-unstoppable undead monster to take control of the Underworld and attack the world of the living. Mercedes saves her kingdom by destroying the Demon King's most powerful weapon that was made specifically to fight against the forces of the apocalypse. Oswald kills two of the last four dragons in the world, who might have been able to help, and in the process completely ruins Velvet's attempt at keeping the ring that can control the doomsday machine safe and out of anyone's hands. In their defense, there's a lot of Because Destiny Says So involved.
King Gallon wouldn't have done a single thing during Armageddon if it weren't for the combined efforts of the heroes and Ingway. Aside from Gwendolyn killing Odette, if Ingway hadn't turned into the Beast of Darkova to try and stop Valentine, Gallon wouldn't have been driven into finally becoming an Omnicidal Maniac by the same curse. If Ingway hadn't also cursed one of the Three Wise Men with the Pooka curse, he wouldn't have had the immortality that came with it, allowing him to retain his power in the Underworld and let Gallon free. If Mercedes hadn't destroyed Odin's psypher, he could've fought off Gallon's forces as soon as they emerged.
Legacy of Kain is made of this. At the end of Soul Reaver 2, Kain discovers that his "edge of the coin" is precisely what the bad guys had been hoping for. Fortunately for him, they weren't quite as omniscient as they thought.
Raziel eventually discovers this for himself, when he finally defeats Kain, recovers the Heart of Darkness, and uses it to restore Janos Audron...only to hand Janos on a silver platter to the Hylden as an incorruptible vessel, and getting rid of Kain in the process.
Even getting to Janos Audron means allowing the Sarafan vampire hunters passage to the sanctuary.
In fact, just about any Temporal Paradox invoked in the series invokes this trope. This stretches back all the way to the first game, where Kain travels back in time to murder King William the Just before he can become the threatening Nemesis, only to cause vampires to be persecuted and hunted down to extinction when he returns to the present.
Deus Ex likes to pull this one on the protagonist. Throughout the game, you destroy everything the enemy has in the way of assets. Generally, this comes back to bite your ass and chew with gusto. Let's take a look at a few.
You retrieve the terrorists' stolen medicines against a deadly plague, and their leader is dead, possibly by your very hand. But wait, they were the good guys, and you just stopped the medicine from getting to a guy who could use it to make more.
You blow up the machine the Big Bad uses to make the plague. The same machine you needed to make the cure.
You save one ally only to lure him into a trap. Unwitting Pawn, thy name is JC Denton.
You retrieve schematics to build your own cure making machine, and the big bad uses you to rebuild his own plague maker. Nice job fixing it, hero.
You redirect the bad guy's nuke at himself, and incinerate innocent US soldiers without even inconveniencing the big bad.
Well, for one, you didn't have to fight through half the US army just to get to him...
This was played in Sonic Adventure where Knuckles was tricked into fighting Sonic. During their fight, the two collided with each other, resulting in Sonic fumbling the two remaining Chaos Emeralds (one of them being green, which Knuckles thought was a piece of the Master Emerald). This gave way for Dr. Eggman to steal them and power up Chaos into his fourth form. So Knuckles allowing himself to get tricked by Dr. Eggman resulted in a Physical God powering up. Considering that this was the second time Knuckles was tricked, Sonic wasn't impressed:
In Shadow the Hedgehog, the PC gathers the Chaos Emeralds... which the Big Bad uses to start stealing the earth's energy. Oops. Hell, Shadow's entire backstory is one big Nice Job Breaking It, Hero. Professor Gerald attempts to create the Ultimate Life Form by allying himself with the Big Bad of Shadow the Hedgehog to cure Maria, then decides to double cross him by building the Eclipse Cannon. Unfortunately, the UN realized that what Gerald was doing was wrong and sought to stop him. The end result saw Maria killed by GUN soldiers, leading Shadow and Gerald to proclaim vengeance on the world. How do they do that? Gerald rigs the Eclipse Cannon (and thus the Space Station ARK) to initiate a Colony Drop once the weapon is armed with all seven Chaos Emeralds. And who's the wonderful person who does this? Why, Gerald's own grandson, Dr. Eggman, of course!
In Sonic Lost World, the basic plot gets started because Sonic rushed into a fight without proper intel:
Sonic: Gone! (kicks giant seashell Eggman was holding into the distance) Eggman's shell is gone! Ha ha!
Sonic: Whatever! When is it a mistake to take your toys away?
Dr. Eggman: When it's the only thing keeping six angry zeti from controlling my mechs, you moronic hedgehog!
Later in the game, Sonic ends up almost triggering a trap, but gets Tails captured instead.
In Dragon Fable, Nythera kills and usurps Warlic using the potions you helped her create. Then she goads the Elemental Lords into attacking Falconreach. So, thanks to your efforts, Warlic is apparently dead and some of the most powerful beings in the world are going to attack your town. Nice going, hero.
Destroying the Super Mega Ultra Darkness Dracolichseems like a good idea. Until it turns out doing this weakens the elemental planes of Darkness and Fire. To make a bad situation worse, Warlic uses too much of his power while creating the light shield and splits into a frail old man and a physical manifestation of his power, which takes on the form of his scary-ass Omnicidal Maniac dad. Nice job breaking it, guys.
Gears of War 2: A certain piece of collectible literature reveals that the Lightmass Bomb that was intended to destroy the Locust stronghold only served to destroy the Kryll's breeding grounds, and had the side effect of awakening the dormant Riftworm which the locusts used to literally undermine the last remaining safe city on the planet.
In Act 3, Niles' AI advises Marcus and Dom not to mess with the main computer. They do, which wakes up the Sires, causing you to have to flamethrowerCHANESORR your way out of the place.
Fate/stay night, Heaven's Feel route, has a villain whose big plan to become immortal involves bestowing incredible power on a certain girl, then using her as a sacrifice. So let's give her that power in the most brutal, abusive way possible, and while we're at it, have her raped on a regular basis! What could go wro— *crunch*. Nice job Breaking The Cutie, Zouken.
In Bomberman 64, the White Bomber travels to the 4 anchors of the Big Bad's floating fortress to destroy its barrier, allowing our hero to confront Altair and prevent him from draining the planet's life force using the Omni Cube. However after stopping Altair, your own ally, Sirius, who was using you to distract Altair and destroy his defenses, steals the cube for himself and begins draining the Planet's life force at a much faster rate. And as an added bonus, he promises to completely destroy the planet afterwards. What a pal.
Used again in Bomberman Hero. Bomberman keeps the last remaining Data Disk safe from the Garaden Empire, collects the other three that they already have, and then returns them all to Princess Millian... who turns out to be Natia in disguise, allowing them to revive Bagular.
Bomberman 64 The Second Attack has two similar cases of this. After confronting the Big Bad who is possessed by a demon, the demon will take advantage of the fact that Bomberman has gathered the elemental stones needed for his full resurrection and siphon the energy from them to regain his earthly form. Depending on certain choices you made previously, the goddess Mihaele may appear after this battle and attempt to use the stones to seal the demon away for good. However, the demon counts on her to try this and ends up sealing her away and absorbing the stones' full power to become an unstoppable god of chaos and destruction.
In Lunar: The Silver Star, Alex needs to get the fourth piece of the legendary Dragon Armor to challenge the Magic Emperor, but the zombified Black Dragon is in his way. He and his allies kill it, but there were only four dragons in the world, and the previous three were already dead by the time Alex got to them or killed right in front of him. Cue the Big Bad's voice gloating that Alex just made it impossible for himself to become a Dragonmaster. With the Black Dragon dead, there are no Dragon Tribesmen left to protect the goddess Althena, allowing him to turn her into a Person of Mass Destruction.
Probably happened one way or another in Shadow of the Colossus. If you ask one faction of the characters and fanbase, the player's character nearly unleashed an ancient and powerful demonic entity that was thankfully sealed again by the Hero Antagonist. If you ask the other major faction, the antagonist murdered the player's character and resealed a neutral or even good ancient and powerful entity who was about to fulfill Their promised half of a deal to revive someone who was sacrificed, all while thinking he was doing a good thing by sealing a demon and stopping a curse. So, either the main character thought he was a hero but broke it by being a Villain Protagonist, or the antagonist only thinks he's a Hero Antagonist and broke it.
In Ōkami, Amaterasu and Issun go off to stop the raging Water Dragon and end up going inside it. There they get the Plot Coupon-y Fox Rods, but in the process end up killing the Water Dragon. Upon escaping from inside the dying Water Dragon, you come across Rao, who you then give the Fox Rods to, but it's only once you've returned to Queen Himiko's palace that you find out that Rao is Ninetails - an impostor who killed the real Rao months ago. Now having the Fox Rods (whose hands - er, paws you were trying to keep the Fox Rods out of), Ninetails promptly kills Queen Himiko, and reveals that because you killed the Water Dragon, there's now no way to reach Oni Island, and with Queen Himiko dead, the location can't be predicted. Oh, did we mention the Water Dragon was the king? Whoops. It's quite the severe case of Nice Job Breaking It, Hero.
His role in revealing the location of the Tomb of Mar, and opening the main chamber, letting Baron Praxis steal the Precursor Stone, which if broken open will destroy the entire universe. And then there's the end of Jak X, when his victory in the races permits Rayn to become the biggest crime lord in the world. Yeah, Jak does this sort of thing a lot.
The Age of Mythology Titans expansion is about Kastor being tricked into destroying all the safeguards the gods had put in place to keep Kronos in Tartarus. Of course, while the player knows this, Kastor doesn't, making going along with the mission objectives the only option.
In Dragon's Lair 2, Dirk the Daring is responsible for quite likely the single biggest Nice Job Breaking It, Hero in HISTORY... or at least the first: He gives Eve the apple, while trying to fend off her advances, an annoying cherub, and two hungry snakes.
The goal of Fruit Mystery is to feed the animals at the zoo. The zookeeper doesn't approve, to put it mildly.
Sora's mission in Kingdom Hearts is pretty simple: Reunite with his friends Riku and Kairi, stop the Big Bad, and smash up any Heartless that may be standing between him and these goals. Except later in the game, the Big Bad Ansem takes control of Riku's body and uses it for the rest of the game. Which means when Sora defeats the Big Bad, well, he pretty much kills one of his two best friends at the same time. Whoops. In the sequel, he gets better, but Sora encounters another problem. All the Heartless he'd been smashing up in the first game? He was helping the real Big Bad accomplish his master plan. Also, those two Big Bads were two halves of the same person, who has recoalesced thanks to Sora killing both halves. Yeah. Nice Job Breaking It, Hero.
In the second game, Sora is tricked into removing the lock that Zeus placed on the Underdrome. Hades is pleased.
Turns out she also made another blunder by deciding against making a young Sora her apprentice in the hopes that he wouldn't have to fight his friend as she had. While this is sensible, as a result, only one Keyblade was sent for two potential users and both Sora and Riku came into conflict over it anyway. Had she marked him, they both would have gotten blades and Sora and Riku could have been allied from the start.
The other two weren't much better. Ven learns that due to his connection with Vanitas, them fighting or coming into contact with each other will create the X-blade, which is so horrible his own master is willing to tearfully kill him rather than risk its creation. Ven's response? Hide himself away and let his more experienced friends deal with it? Nope, he charges right off to fight Vanitas anyway, which of course creates the X-blade. He manages to destroy it, but only by causing massive damage to his own soul, forcing him into a 12 year coma. Meanwhile, Terra learns that his mentor is evil and was prodding him into using darkness-based powers to further his evil plan. Does Terra promptly stop using darkness because that's what Xenahort obviously wants him to do? Nope, he tries to fight Xenahort with the darkness instead, which leads to Xenahort taking his body from him. Like Ven, Terra manages to salvage a total disaster at the last minute by having his armor and keyblade move on their own and KO Xenahort, stopping his current plan, but Terra's still short one body now.
In RuneScape, the quest 'Spirit of Summer' ends with the spirits telling you that Summer's great plan to defeat the Big Bad turned into this trope: instead of hurting the Spirit Beast, you just made it stronger, starting the sequel, 'Summer's End'.
And in the quest 'Enakhra's Lament', you get enlisted to build a statue and end up solving the puzzle in a temple, ending with you liberating an entrapped spirit and attempting to capture his nemesis, who breaks out and they both flee. Then the guide throughout, Lazim, is furious at you because he wanted to learn from the Mahjarrat spirits, but you freed them, effectively ruining his chances. This makes Lazim Too Dumb to Live — wanting to learn is fine, but actually believing that they wouldn't kill him in a second was stupid.
RuneScape is fond of this trope. In another quest, 'Priest in Peril', the bad guys get you to kill a Guard Dog that was preventing them from polluting the Paterdomus temple and the Salve River. Said temple and river are the only things that's keeping the evil in Morytania from invading.
Another one: the quest 'Shadow of the Storm', where you are told to help summon the demon Agrith-Naar so you can kill it for good (being in its own dimension gave it more power), only to find out that the demon was already in the world, and trapped in a much weaker human form, and you actually sent it back to its own dimension and freed it of being trapped in human form. Nice Job Breaking it, Player.
And see, in the end of Summer's End, you've destroyed the Spirit Beast... and now it's in the physical realm and even MORE dangerous. Oh Crap.
Although it can't get any stronger and can be killed in the physical realm. It's still the most powerful known thing in the world, but it isn't invincible.
During the quest Temple of Ikov, you are given the choice to follow this trope. A frail hooded man named Lucien will ask you to retrieve an artifact known as the Staff of Armadyl. After running through a few trials, and finally reaching it, you are now forced to kill several guardians of the staff (who are dressed in a way that almost obviously makes them good guys), and then, upon gaining the staff and bringing it to Lucien, he thanks you by taking it and then laughing maniacally. It's probably worth noting that this is the same staff that Lucien will later use to kill a lot of your friends and mentors. Nice Job Delivering it, Player.
And then after killing those friends and mentors during While Guthix Sleeps, the player goes to the Stone of Jas and destroys the beings defending it, allowing Lucien to walk in and steal it himself.
For most of Silent Hill 1, Harry runs around the town finding and neutralising the Marks of Samael that Dahlia claims are causing "the darkness" to encroach upon the town. Of course, they're actually Seals of Metatron, placed by Alessa to prevent the power behind the darkness from increasing in strength, not only causing the two worlds to collide in an even more nightmarish monument to Chaos Architecture, but weakening Alessa enough for Dahlia to capture her and use her in the ritual to birth "God", resulting in the death of Harry's daughter and the permanent transformation of Silent Hill into a malevolentGenius Loci. Thanks a lot, Harry.
Nice job destroying SHIKI in a way that makes you swallow his and more importantly Roa's persona, Akiha. Made you a totally crazed yandere with emotional restraint issues. Plus essentially turned Shiki into a breathing corpse because he couldn't get more energy from SHIKI, And turned yourself into a bloodsucking monster that admittedly didn't kill its victims, at least. And... well, we'll just stop there, hm?
Neck, back of the head, from the right eye to the lips, Upper right arm, lower right arm, right ring finger, left elbow, left thumb, Middle finger, left breast, from the rib bones to the heart, two places of the stomach to the abdomen, Left crotch, left leg thigh, left leg shin, all of left foot toes. As I went past her. Without even taking a second. Literally at a blink of an eye. I "dissected" her into 17 pieces of meat.
In Crackdown, you, the Agent, end up being a massive Unwitting Pawn who took down all crime syndicates so the Agency could roll in over their former territory and control the city without complaints. Keep in mind the Agency had bankrolled the gangs in the first place to cause a bigger panic. Nice job creating permanent martial law, hero. Although since you can play the game as a Sociopathic Hero who mows down pedestrians without much trouble, you just might not care.
In the sequel, Pacific City is plagued by mutated monsters that even the Agents have a hard time dealing with. Why? Because when the Agent whacked a Shai GenMad Scientist, he inadvertently released the mutants in said scientist's lab.
Happens twice in Killzone 2. The first time, Rico ignores Sev's plan to rescue the rest of their squad and the scientist, resulting in Garza's death. The second time, Rico ignores their orders to arrest Scolar Visari and Visari's warnings of what would happen if he died, resulting in a large Helghast fleet arriving to what's left of the ISA invasion force.
Killzone 3 as well. The protagonists attempt to destroy the Big Bad's doomsday-device toting space cruiser utilizing stolen fighters. The crippled ship attempts to power down its destabilized warp drive and land, and Sevchenko destroys the ship with a nuclear missile... Setting off its warp drive and payload of unstable missiles, setting off a chain-reaction that eradicated all life on Helghan. Made worse by the fact that the missiles that triggered this kill by causing living things to explode violently. Yeah. Nice job.
That last one is debatable given that the entire Second Extrasolar War was decisively ended with that single nuke. Sure, the outcome might have been morally dubious at best, but when you look at it objectively, it's a total victory for the ISA. It only falls under the category of "breaking it" if you support the Helghast.
Paladins Quest for the SNES begins with a particularly huge example. On a dare, the Player Character, a thirteen year old student Spiritualist (the setting's term for a magic user), sneaks into the abandoned and spooky tower on the school campus. When he reaches the top, he pushes a big shiny button. This awakens Dal Gren, a biomechanical terror from ancient times that nearly destroyed the world about 10,000 years ago. Said monstrosity immediately knocks the poor sap unconscious, lays waste to the magic academy, kills everybody else there in the process, and flies off to destroy the rest of the world. Um, oops?
This happens in The 7th Saga after you manage to recover all of the Runes. Turns out the king who sent you on your quest was actually the time traveling Big Bad Gorsia in disguise. The runes he sent you to find were the seals on his powers, which you practically handed to him on a silver platter. He rewards you by blasting you so hard you go back in time thousands of years. Then he goes back in time also to get revenge on the hero who defeated him the first time. Yes, the reward for all of the Level Grinding up to that point is finding out that the world would have been better off if you had just let that first wandering monster eat you.
Though it should probably be pointed out that only one of the possible characters is actively trying to be a hero, the others are in it for personal gain. Hell, one of them is a demon who wants the power to rule supreme.
The three factions of Supreme Commander spend the whole game fighting over control of Black Sun for their own purposes; no matter who seizes control of it in the end, firing it opens a rift between this world and the quantum realm, allowing the Seraphim to start a rampage of human extermination across the galaxy continuing on the expansion.
In Bleach: Shattered Blade, the main plot takes place as a result of the destruction of the Sokyoku, which releases an ancient arrancar that was sealed. In the story mode, the main character gathers the pieces, which results in their coming face to face with the arrancar in the last battle.
In The Conduit, Mr. Ford spends the first half of the single-player campaign trying to stop Mr. Adams, but ends up unintentionally giving the President of the United States evidence to turn over all executive power to Adams instead.
Prior to the events of Shoot 'em UpBattle Garegga, the Wayne brothers are given a contract to develop new advanced vehicles and weapons for their government. One year later, the government tries to Take Over the World. The brothers then set off in two Super Prototypes and spend the entire game fighting the war machine they helped create.
Guybrush Threepwood of the Monkey Island series has a nasty habit of invoking this trope, from willingly surrendering a piece of the Ghost Pirate LeChuck's body to Largo LaGrande so that he can resurrect him in Monkey Island 2, and proposing to Elaine Marley with a voodoo-cursed ring that freezes her into a golden statue in The Curse of Monkey Island, to screwing up a voodoo spell and spreading LeChuck's evil voodoo pox all over the Caribbean in Tales of Monkey Island.
Speaking of Tales, this spreading of the Pox of LeChuck is followed by Guybrush's use of the MacGuffin Esponja Grande to absorb and remove the pox from everyone in Chapter 4, curing them completely, so that LeChuck can obtain it for himself, killing Guybrush in the process. Nice job curing everyone and getting yourself killed, Guybrush.
And in Chapter 5, when Guybrush (as a Ghost Pirate) finds a spell so he can escape the Crossroads and return to the living world, he opens up the rip in the Crossroads and inadvertently (along with LeChuck's hypnotized monkeys) lets the villain use La Esponja Grande to harness the voodoo power from the Crossroads, creating other rips and becoming the Demon Pirate God of the Caribbean who turns a willing Elaine into his demon bride. Nice job making LeChuck more evil, Guybrush! However, creating other rips lets Guybrush find a way to repossess his own corpse and shrink the sponge in order to free Elaine from LeChuck's influence. So nice job negating your breaking it and averting the destruction, Guybrush.
This has been the premise for the other classic LucasArts game, Day Of The Tentacle. Though there was a request for a rescue from Green Tentacle, Bernard also frees Purple Tentacle, who gained a thirst for power, which is why their creator Dr. Fred tied them both up in the first place. Purple Tentacle runs off to resume his conquest, leaving Bernard bearing the realization of his mistake.
In Quest for Glory, this happens at least once each in Trial by Fire, Wages of War, and Shadows of Darkness. In these cases, the Stupidity Is the Only Option trope is averted, as the Hero is either being magically forced to help villains, or could not possibly be expected to foresee the results of his actions.
In Trial by Fire, you are mind-controlled into helping the Big Bad find and retrieve the artifact he plans to use to conquer the world. Failure to fix this will in some cases lead to a 'Game Over' message concerning the look of surprise on the Big Bad's face when he realizes he bit off more than he can chew.
In Wages of War, the peace conference you spent the entire game arranging goes catastrophically sour and has the exact opposite of the intended effect.
In Shadows of Darkness, our hero is once again dominated into helping the villain, this time through the use of a geas, a magical means of forcing certain behavior. By the time the terms of the geas are complete, the Hero must initiate the Apocalypse in order to avert it.
Shadows of Darkness has a more minor one as well; the innkeeper's daughter is missing and assumed dead, and (being a hero) you have to rescue her. Unfortunately, the child is currently a vampire in the service of "Aunt Trina," the above-mentioned villain, and they actually like each other; resurrecting Tanya and bringing her back to her parents is what pushes Trina's Berserk Button and ultimately leads to her geasing you. Oops.
Regardless of your actions in Shin Megami Tensei If, you always eventually discover that the Demon Emperorturned Akiko and Ryuuichi into stone statues. However, your choice of partner influences which themed worlds you enter during your quest; if you enter the Wrath world, you witness Ryuuichi's futile attempts to rescue Akiko, then eventually come across their statue. The Demon Emperor baits you with "Smash the statue and you might save them!" Even if you don't bite, your partner leaps at the chance, resulting in a sadly very literal example of "Nice job breaking it, hero..."
In Shin Megami Tensei IV, you're tasked with releasing three prisoners kept sealed in Kagome Tower. Long story short, before long you might wish you just had left them there to rot.
Ace Combat X: Skies of Deception offers you a few opportunities to "break it". You can ignore the Miller Unit poised to take over Port Patterson, forcing you to have to backtrack to save it. You can ignore the Hamlet Unit and whatever they're planning, forcing another backtrack when they take over Santa Elva and end up dealing with That One Level. You can let Leasath transport planes get to Griswall by going after jammers first, allowing the enemy superweapon to get a nasty upgrade. At the final crosspath, the game forces a Sadistic Choice on you that will strengthen the Fenrirs in the final missions one way or the other.
Wario Land 3 has Wario collecting various pieces of treasure for the entire game, to help a hidden figure in an ancient temple (and presumably, escape the pocket universe in which he's trapped). However, after you collect all the pieces of treasure, a music box song plays... then it turns out that the hidden figure who's been manipulating Wario is Rudy the Clown, the game's Big Bad. Cue final boss battle.
Wario World has the entire plot started by this. It's Wario's plundering of a black diamond deep in the jungle that unleashes the ultimate evil... the Eldritch Abomination / Artifact of Doom that's the Black Jewel itself, which proceeds to turn his entire castle into a parallel universe filled with monsters.
In Pokémon Mystery Dungeon: Explorers of Time/Darkness/Sky, you and your partner Pokémon, along with the rest of Wigglytuff's Guild, help to track down Grovyle, the thief who was stealing the Time Gears, the removal of which was stopping time in areas around the world and causing Pokémon to go berserk. After he is caught, you and your partner are dragged into the future by Dusknoir, the Pokémon who had practically become a mentor to the two of you. As it turns out, Grovyle, Dusknoir, and you are all from the future (though only Dusknoir knows about you being one of the future folk at this point). Grovyle was gathering the Time Gears in order to bring them to the Temporal Tower, the place from which Dialga controls time. Because the Time Gears had somehow been scattered, Temporal Tower began to crumble, along with Dialga's sanity, to the point that in the future from which you, Grovyle, and Dusknoir once resided, Dialga has become Primal Dialga, a being whose only concern is self-preservation, at any cost. Oh, and did we mention that by you stopping Grovyle from completing his mission, the three of you have now been trapped in the future with very little hope of returning?
This shows up a few times in Dragon Age: Origins. One notable example is the "Summoning Sciences" sidequest. One of the spirits you summon during the quest is "The Trickster". Later, the Chantry Quest Board has a quest called "Unintended Consequences", which requests that someone stop whatever is killing people on a certain trade route. When you accept the quest and investigate, it turns out that the Trickster you summoned is the one killing people. Oops. Somehow it doesn't feel right accepting a reward for cleaning up a mess you started.
Due to the Grey and Gray Morality and tricky politics in Orzammar, it's all too easy to make things worse in the long run. Picking the "honorable" Lord Harrowmont to be the new king leads to Dwarven society being even more isolationist and bound to its caste system (screwing over the casteless). Picking Magnificent Bastard Bhelen (emphasis on "Bastard", especially if you picked the Dwarven Noble Origin) OTOH, will end isolationism and the abolishment of the unfair caste system. Also, helping one dwarf to open a Chantry branch in Orzammar may seem like the right thing to do at the time. In the epilogue, this leads to him being murdered by other dwarves who don't approve of his efforts, which leads to the Chantry seriously considering launching an Exalted March (read: Crusade) against Orzammar.
In Planescape: Torment, in order to learn the whereabouts of your mortality, you must free the angel Trias from his imprisonment beneath Curst, a town populated entirely by liars and betrayers. Sounds good, right? After all, freeing an angel is a good deed, right? Wrong. When you get back to Curst from your next destination, you discover that Trias has turned the entire town into one big human sacrifice, causing it to slide into the prison plane Carceri, where all of the inhabitants are being slaughtered by demons. Why? Because the lives of the townsfolk are a payoff that will allow him to raise The Legions of Hell and invade and conquer Mount Celestia. Wow, did you ever screw up.
In Devil Survivor, you have a choice of five ends, four of which directly aim to solve the problem of the oncoming war between demons and angels (or be a part of it). Then there's the fifth option: choosing to support your increasinglypanickyWhite Magician Girl Yuzu and the Action SurvivorDeterminator Honda to desperately escape the Special Defense Force blockade and evade judgment. Hooray, you've managed to kill innocent civilians, shirk your duties, and live another day! ...right? Ha. Metatron, angelic second-in-command to God Himself, sends you an email from heaven and tells you that you have just damned mankind to an endless hell where demons roam free and only the strong survive. The entire point of God's Ordeal was that mankind needed to prove it could reject the temptation of demons. And as the reincarnation of Abel, you're pretty much the defining person to exemplify humanity; i.e. it all depends on you. To clarify, God is supportive of you even if you use demons to make Japan a world superpower, or decide to break the game and banish the demons without divine intervention, and he's even willing to accept your decision if you become King of Demons and lead them against Him, and He's not okay with this. Believe it or not, being The Chosen One means something.
Even the Gigolo (a.k.a. the Norse god Loki) chews you out for taking this route, and he was only involved for the lulz.
Super Smash Bros.: In all three installments of the series, though mostly the original and Melee, the single-player mode ends with the player character killing their creator and the entire Smash Bros. world being destroyed.
Also, in Melee, the player turns Bowser into a trophy, unleashing Giga Bowser as the final boss of Adventure Mode.
At the end of ToeJam & Earl, the guys are received as heroes for surviving a visit to the most dangerous planet in the known universe: Earth. That is, until it's discovered that a large number of Earthlings followed them back and are trashing the planet. ToeJam and Earl set out to solve the problem themselves, presumably to avoid being punished for it.
In the original game, if you play a two-player game and one player opens a total bummer present when both characters are near each other, the other character will say "Thanks a lot" before they both die.
In the first Baldur's Gate, a sidequest has you escort a poisoned man to a nearby temple for treatment. Later on, a Flaming Fist mercenary (essentially the police force of the game) reveals that the man you helped actually betrayed the Fist and stole several magical items and gems. Nice job helping a criminal walk free, hero.
In Splinter Cell Conviction (not too sure about earlier games) destroying a light, if noticed by enemies, will result in them using their flashlights. Subverted as, depending on the situation, it may be a worthwhile tradeoff.
Conviction also has a stereotypical GonkHollywood Nerd and Sam Fisher fanboy who gives him his goggles, which are needed to bypass all the security tripwires he designed the algorithms for. Nice job being a huge Metal Gear/Resident Evil fan, Poindexter.
In Wild ARMs 2, it's not the hero who breaks it, it's the Magnificent Heroic Bastard. Irving spends the entire game orchestrating the plot to save the world, making many "necessary sacrifices" along the way, up to and including sacrificing himself and his sister to give a physical body to the Eldritch Location threatening to consume the universe. While this succeeds spectacularly, it has the unfortunate side effect of tearing the heroes apart emotionally. And the main character happens to have a demon sealed inside of him that feeds off of negative emotions. A demon that Irving put there to give the hero a Super Mode. D'oh!
In Dungeons And Dragons Heroes, you spend the bulk of the game unlocking and traveling through several rift portals in order to combat the Big Bad's minions in various worlds. However, when you finally face the Big Bad, he reveals that because you unlocked all the rifts, he was able to regain his full power. Whoops.
The entire premise of Epic Mickey. The plot started because Mickey just had to mess around in Yen Sid's studio.
In The Adventures Of Rad Gravity, you spend the entire game trying to defeat the wizard Agathos, who is trying to prevent you from linking up the benevolent supercomputer network. Then when you finally beat him, you learn that he was a good guy, that linking up the supercomputer network will be catastrophic to the galaxy, and that the evil mastermind has been your ship's helpful onboard computer, Kakos, the whole time.
Mass Effect 2. What, now? You sold Legion off to Cerberus? Congratulations, now no one will stop the Reaper Virus from overtaking the normal Geth, turning them all into Reaper minions. The bad Geth are now 20 times stronger. And even worse,Legion's absence makes it impossible to avoid genocide of either the geth or the quarians in the third game.
Taking down Saren and Sovereign at the end of ME1? Good work, Shepard — now the Reapers are interested specifically in your species. Cue the Collectors raiding human colonies... and then, the events of ME3...
This might go without justification as Shepard deliberately releases all prisoners of a maximum security space station just to recruit a peculiar squad member. Mind you, every single one of the prisoners were mentally unstable bloodthirsty psychopaths, though they are almost all eventually recaptured.
Mass Effect 3 can lead to several Paragon decisions turning around and biting you in the ass. For instance, telling Kelly Chambers to stay on the Citadel and help Cerberus victims gets her killed when Cerberus invade the place. Sparing the second Rachni Queen, if you killed the first one seems like a great idea, too, until it turns out she's indoctrinated and attacking your war assets.
The worst ending is a prime example. The Crucible misfires, wiping out Earth, and that may be preferable given that all endings destroy the mass relays, cutting off Earth from any aid, making sure that instead of dying immediately, it'll die slowly.Nice job. The Extended Cut changes this so that in all but the absolute worst Destroy ending (which you can only get if you deliberately play the game badly) the relays are only damaged, not destroyed, and the galaxy is shown rebuilding itself.
The Extended Cut adds the choice for Shepard to refuse the choices presented to them for the Crucible. How badly does the hero break it in this case? It results in the Reapers wiping out all galatic civilization once again. They're eventually stopped by the civilization of the next cycle…who don't pass up the opportunity to use the Crucible against them.
Heroes of Might and Magic IV reveals in its introduction that all the effort the heroes put into Might & Magic VI, Heroes III, Might & Magic VII, and Might & Magic VIII was a complete waste of time because Gelu decided to wield Armageddon's Blade in single combat against a barbarian carrying the Sword of Frost. Turns out that the clash of those blades causes the complete and total destruction of the entire planet! Well, nice job causing an Earth-Shattering Kaboom, Gelu. Dunce.
Might and Magic VII has an example internal to the game itself: the first few player quests are about rebuilding Castle Harmondale and being recognised as Lords of Harmondale (you got the the title in the tutorial, but you're advised that no-one really takes it seriously). You succeed... which leads to Harmondale becoming an important prize again, triggering another Timber War between two of the 'Good Guy' nations. Granted, if your characters decide to take the opportunity to align with the Path of Dark this leads to, the war itself is a perk, it's the fact that it (in terms of plot, if not in what it can actually lead to in-game) puts your rulership over Harmondale at risk that's the problem.
It turns out that by running from the zombie outbreak and preserving their own lives, the survivors of Left 4 Dead and Left 4 Dead 2 have been aiding the spread of the infection. Oops.
Heavy Rain has Scott saving Lauren from drowning in his car. However, if Scott survives his encounter with Ethan/Norman/Madison by virtue of successfully killing whoever managed to reach the warehouse, Lauren will find out that he is the Origami Killer and kill him.
Dante's Inferno: Dante must break large links of chain in order to progress through the Inferno. Satan later reveals, "My salvation for breaking the chains of Judecca."
Poor Spyro from the reboot trilogy just wanted to save the girl he loved from getting turned evil and the Ultimate Evil from being unleashed. Then, after killing that game's Big Bad, he freezes them in time to protect them from a collapsing mountain. Turns out that Cynder was being unknowingly used by the Dark Master to lure Spyro to the Well of Souls because he needed Spyro there to get free. And by freezing himself and Cynder in time, it let Malefor run rampant for 3 years unchecked and awaken a planet-destroying monster. Though in Spyro and Cynder's defense, Malefor may have just lied to screw with their heads.
NieR has a pretty big one. No matter what ending you get, Nier destroying the Big Bad causes the Gestalts to effectively die out. No Gestalts, no Replicants. No Replicants, no humanity. In Nier's defense, though, there was no way either he or the player themselves could possibly have known this. (Indeed, this is only revealed in a Japan-only infobook, and the same source goes on to describe a small Hope Spot in regards to ending D.)
It's actually even worse than this. Nearly all of your plot-advancing actions ensure that humanity will die out, and all the sacrifices made to stop this are now worthless. The only exceptions are some random odd jobs that are completely optional. NieR is "Nice Job breaking it, Hero" — the Game.
In Illusion of Gaia, there's the subquest of collecting 50 red jewels, littered all over the world, to get the jeweler's "secret". Turns out the secret is that the jeweler is actually one of the endbosses from the kind-of precursor Soul Blazer. And collecting the jewels restored his power. Oops...
Thankfully, there is little consequence either way. It's just a Bonus Boss: a pretty tough one given that you don't have the same set of moves the other game's hero had.
Aura is the one who broke it first, by leaving The World. This caused CC Corp to try and restart the original AI creating algorithm of Harald Hoerwick's code to create a new Ultimate AI. This lead to a failed Batman Gambit between Jyotaro Amagi and Jun Bansyoya, which destroyed The World (R:1) and caused the release of the captured Eight Phases of Morganna. This caused the creation of The World R:2 and the reintallation of the Harald Folders, which fuelled the generation of AIDA from the loss of Aura. This allowed Tri-Edge to kill Aina and infect Ovan, which caused Ovan to follow through with a Xanatos Gambit so that Haseo could get strong enough to destroy him. This put Ovan into the unfortunate position of letting Shino get PK'd, causing Haseo to turn into an Ax-CrazyBroken Bird, and that caused immense frustration for everyone (especially Tabby and Atoli). Finally, Ovan's plan would cause just what Jun feared by creating a new Cubia; and, Yata, who was working off Jun's notes and should have known better, let Haseo go through with it, blinded by their mutual obsessions with Ovan. Everyone broke it!
The protagonist Lazarus Jones from Ghosthunter basically couldn't keep his hands to himself and pressed a switch which freed all the captured ghosts in the ghost array (kinda like the original Ghostbusters). Then poor Jones had to take up the job of re-capturing them.
The Zork series is full of these, but the best example is in Zork Zero, where you have to fill in some bottomless pits to get past a specific area. Oops, you let out the infamous evil creatures of darkness... grues. Thanks.
Ecco the Dolphin managed to save his pod in the first game... but accidentally broke the timestream in the process. Good job, dolphin, now go fix it before the aliens take over.
In the very beginning of Singularity, the protagonist is dragged back in time and saves a Soviet scientist from a burning building. Not only does this advance a dangerous project far beyond where it would have gone, but the man becomes the game's primary antagonist and the ruthless dictator of the world.
Even his attempt to fix what he'd broken breaks the world. If the player chooses the good ending and goes back in time to kill himself as he saves Demichev, he reawakens at the beginning of the game with his memories intact, and multiple clues indicate that the good scientist used his Time Manipulation Device to unite the world...under Soviet rule.
Clive Barker's Undying: First Patrick discovers that, by using the Scythe, he's been unwittingly collecting the souls of the Covenant siblings for Jeremiah. When he tries to fix that by killing Jeremiah at the Standing Stones, he creates the necessary sacrifice to bring forth the Undying King. Oops.
Rather, "Nice Job Breaking it, God" in Jericho. His first creation, before Adam and Eve, was a terrifying nightmare that was neither dark nor light, male nor female; embodying everything and nothing. So he decides he doesn't like it and throws it in the Abyss like an unwanted puppy. Naturally, it is unhappy with this and spends all of its existence trying to escape and wreak havoc.
In Strife, you are given a choice of missions early on by the corrupt governor. One is to investigate and destroy a tap connected to the local power main. What you aren't told is that it's your La Résistance power tap which prevents the rebel base from being discovered. Blackbird, your Voice with an Internet Connection, is quite unhappy with you afterwards.
Dead Space 2: In his attempts to survive the second necromorph outbreak, Isaac makes quite a mess... first they dig the codes out of Isaac's head to make a new marker, then he and Elie drive a giant drill though the originally necromorph-free government sector, then he takes down a barrier stopping them getting to the marker, triggering a convergence event, then due to massive damage, the main reactor overloads and explodes, destroying an entire city. Oh and this is the second time he's been the pawn of a manipulative marker.
Near the end of Dragon Age II you gather the components that Anders claims he needs to finally separate him and Justice/Vengeance. They are actually spell components he needs to blow up Kirkwall's Chantry, an act that kills off the only people who could have brokered peace between the Templars and the Circle mages in Kirkwall. Congratulations Hawke, you just helped a terrorist murder innocent people in order to start a war. Of course, it's also a no-win situation due to extreme use of Stupidity Is the Only Option: you can't prevent this from happening no matter how you behave.
Hawke and company also broke it earlier when they discovered the Primeval Thaig and the cursed lyrium idol. And Isabella broke it before the game even started when she stole a sacred Qunari relic. And in the end, no matter which side Hawke takes, his/her actions inspire one side of the Templar-Mage war.
It is only this trope if you don't agree with Anders. If you do, however, this is just a rather extreme way to start a much-needed revolution.
Though even then, some plan that allowed the mages to be the ones to strike the first blow instead of being forced onto the defensive might have been preferable.
RPG Shooter: Starwish has a particularly large-scale one in its backstory. The plan was to briefly turn the star of an inhabited planet into a gateway, long enough to pull through another planet whose own star had been destroyed, saving the latter planet and its people. Instead, the star turned into a black hole, wiping out the former planet and everyone on it.
A variant is attempted about two-thirds of the way through the game. It succeeds, but only afterward does the instigator realize this has released the Big Bad, who starts going after the planet she had been trying to return to all along. She is not happy about this.
And then there's the main character's Be Careful What You Wish For, which is both smaller (a child's angry wish) and larger (motivates the Big Bad to destroy all sentient life).
In Dungeons & DragonsDaggerdale, defeating the Big Bad Rezlus paves the way for your "ally" Nezra's Cyric loyalists to take over the tower. She is at least gracious enough to give you a chance to run.
Albion. While looking for a guide to lead you to the passage that takes you to the Toronto, you have the option to break out a dangerous serial killer with a ridiculously bogus excuse for why she was locked up from prison. The first thing you find when returning to the city is a crying little girl whose mother was killed by an evil lady. There's a reason walkthroughs will ignore the prison.
The Umajo Prison. Don't go there. Seriously, it's not worth it. Or if you're really so curious, whatever you do, do NOT free Nelly. Let the murderous bitch stay in her cell.
Mizuhara steals Toko's medicine in Kara no Shoujo because she believes it's an illegal drug and a present from Reiji, of whom she is jealous. This ends up getting Toko hit by a car, having all her limbs removed, getting kidnapped, and finally dying. On the plus note, she doesn't have to see the full consequences of her actions since she gets murdered about five minutes later.
The first half of Ratchet & Clank: Going Commando is spent chasing down a thief who stole an experiment from Mega Corp.. Then, after that mission's accomplished, they then learn that the "experiment" is a blue, furry ball of ferocious death that Megacorp (which is unknowingly under the control of a comeback-obsessed Captain Qwark) plans on mass-selling across the galaxy. Oops, indeed.
In The Orion Conspiracy, Devlin is forced to do this. He is being chased by a xenomorph, and he sets a trap in the engine. He lures the xenomorph onto an exposed power cable, only to find out that the xenomorph is too tough to be killed outright by electrocution, and that it was only stunned. So he ends up opening up fuel containers, making a Lampshade Hanging on how unsafe this is, spills liquid gas onto the xenomorph, and runs off, while the xenomorph ends up on fire and explodes. Unfortunately, Devlin finds out shortly afterwards that by doing this, he wrecked up the engines of the space station, and that the station is now in danger of falling into the black hole nearby. Now he has to fix this! Nice Job Breaking It, Hero, indeed!
In The 3rd Birthday's ending, it was revealed that Eve Brea's desire to save her sister Aya from death caused her Overdive ability to awaken and took control of Aya's body to fend off the SWAT team. This caused Aya's soul to shatter and eventually creates the beings known as "Twisted". Eve's weakened body also gave birth to the "High Ones", whom will engage in a future doomsday war with the Twisted as well as humanity.
In Tomb Raider: The Last Revelation, it is Lara Croft herself who unwittingly releases the Egyptian god Set from his sarcophagus. Needless to say, he's not happy and bent on bringing about the apocalypse.
Arc The Lad has one even earlier, in the first game. The token female character puts out a three-thousand-year-old flame that has been burning on a sacred mountain in order to escape an arranged marriage. We find out that this flame had been keeping the Big Bad's cage sealed away, which led to the entirety of this game and its sequel trying to recover and reseal this cage, called the Arc. In the end, they failed anyway and the Arc is destroyed.
The Reconstruction. Dehl leaves Havan behind at the end of chapter 5, who then proceeds to slaughter the Watchers and take over the world. Dehl also allowed Havan to get the Chekhov's Gun that drove him to do that in the first place.
Dehl broke it before the game even started; he brought the Blue Plague to the mainland via Moke, though it did abruptly end the revolt, saving some lives...which were probably then taken by the Plague anyway.
And Father Sikohlon broke it even before that by creating the Plague in the first place.
L.A. Noire has one in Wham Episode, "Manifest Destiny". Cole cheats on his wife for Elsa. This is bad news because he gets suspended and demoted to Arson, thanks to Roy having followed him.
Even more dramatically. His actions in World War II have started two things. Courtney getting jealous of his success that he is going to rob the US Coolridge for morphine, and Ira going crazy after he is ordered by Cole into burning the civilians in a cave.
In the 2007 Conan game, the title character broke the seal statue that imprisons the Big Bad Graven at the beginning of the game and the hero has to stop him throughout the whole game.
You release a girl from a dungeon in Fantasy Quest, thinking her the princess you're seeking. You quickly learn that you're wrong, but later info reveals that she's actually a mass murderer. She was in PRISON after all...
In Fable, specifically in the lost chapters version, at the end of the game the player must collect several souls in order to open the way to the final boss Jack of Blades, whose true form is revealed to be a huge dragon, which you must defeat. Sounds like a good idea, right? However, killing the final boss is in fact completely unnecessary, as even Jack states that he would remain sealed up and never able to escape if the player had never opened up the path to him in the first place.
Given that unless he is killed he will still be free to screw the world up through his mask, even if you didn't free him, he would still be out there causing suffering to everyone.
In Fable III after you defeat Logan and take the crown, you then discover that he was actually being such a tyrant so as to protect the kingdom from a much larger threat in The Crawler.
In Dragon Ball Z: Budokai Tenkaichi 2, you can toss around huge explosive effects that, in the series the game is based off of, are capable of destroying the planet. Consequently, if you hit your opponent with one while they are standing on the ground (or if you miss them entirely), you are treated to a lovely cut scene of the Earth (or Namek, if that's where you are fighting) getting hit by your planet-killer attack, and the rest of the battle is fought on the surface of your dying world complete with fire and earthquakes. Nice job breaking it. Although, as this is an on-the-rails fighting game, the planet will be back to normal in the next stage.
In Titanic: Adventure Out of Time, if you complete all the three objectives, you prevent World War I and the rise of Nazism and Communism. If you complete just one or two, you make the world much worse, with either Nazis or Communists taking over Europe.
In AdventureQuest, your character unknowingly sets the tyrant King Awethur free from his imprisonment in one quest. One of the NPCs even says "Nice job fixing it, hero."
In The Last Stand: Union City, the game ends with you and Jack and Co. blasting open the wall into the last uninfected area in the city. A unstoppable horde follows quickly. To make matters worse, you actually have to kill some of the defenders on the way in, basically ensuring the entire base will be killed.
The aim of Lollipop Chainsaw is to defeat all of the Dark Purveyors and stop the Big Bad before he can perform his sacrificial ritual, right? Well, how's this for a twist? The sacrifice turns out to be the Dark Purveyors that you kill, as well as the Big Bad blowing his own head off in order to offer himself as the final sacrifice for opening the gate between Earth and Rotten World, allowing Killabilly to cross over. Damn.
In the Valkyrie DLC for the iOS game Galaxy On Fire II, your character Keith Maxwell is hired by a mysterious woman named Alice to do various tasks for her, paying you huge amounts of money for them. Eventually, however, you realize that she's actually the sister of your Love Interest Carla, who wants to steal Khador's instantaneous FTL drive and sell it as her own invention. So, Keith decides to go to Alice's Space Station and confront her about it. He ends up letting it slip that he has a Khador Drive on-board his ship. Alice quickly confiscates it, as well as the coordinates of the Deep Science space station (where Khador's lab is located), which she plans to destroy to remove any competition. Oops.
Overlaps with Evil Is Not a Toy in Immortal Souls. At one point, the lead heroic vampire character finds himself having to escape from a base full of fellow shadow creatures that the Hero Antagonist Templars also captured to study. He decides to free them, thinking they'll help distract the Templars. Which they do... but they also attack him, as it turns out they're too evil/mindless to be grateful or even care. Oh, and they also go back to attacking the normal humans which the Templars were partly trying to protect by capturing the monsters. Well, whoops. The Templar leader even asks, "Are you happy now?"
First, in chapter 10, "The Wish Seed," they kill the Phoenix, thus allowing Hades to set his master plan in action by tricking the humans into going to war.
Then, in chapter 13, "The Lunar Sanctum," they destroy the titular Lunar Sanctum. It isn't until several chapters later that it's revealed that the Lunar Sanctum was actually a prison for the Chaos Kin, and Pit's attack allowed the creature to escape, after which it possesses Palutena, nearly eats her soul, and traps Pit's soul in a ring for three years while the whole world goes to Hell.
In one of the chapters of Heroes Chronicles, the "hero", Gelu, goes out to destroy the Sword of Frost with the Armageddon's Blade. However, doing so will destroy the world, so it's up to the player character to find the Sword before Gelu does. At the end of the chapter, you find out that Kija, a barbarian who wants to give said weapon to her husband Kilgor, got to it first and took it. Guess what happens next.
To be more exact, Gelu is entirely correct in that the Sword of Frost can be destroyed by Armageddon's Blade. His mistake is in assuming that it is as easy as that, rather than the complex ritual it actually requires if you want to avoid the world-destroying consequence.
In Divine Divinity, the Divine One defeats the Demon of Lies but fails to prevent him from summoning the soul of his God of Evil incarnated in an infant boy. The Divine One couldn't bring himself to kill an innocent baby and he tried to raise the boy Damian as his son. Tragically, the sequels show that it didn't work out. Worse, even after the Divine One realized Damian was evil, he could not bring himself to kill him. The world suffered because the Divine One couldn't help but think of Damian as his son.
A central theme in Spec Ops: The Line, wherein the actions of the protagonist make absolutely everything worse. In his attempts to be the hero, Capt. Martin Walker massacres countless American soldiers, launches a white phosphorous strike on civilians, and destroys the water supply. By the end of the game, he is bluntly told that everything would have been better if he had just stopped.
In Saints Row IV, the alien villain drops the protagonist into a simulation, warning him/her that he will destroy the earth should he/she escape. He/she does. He does. Congratulations.
This action actually turns into a bizarre double case of "Nice Job Breaking It, Hero" and "Nice Job Breaking It, Villain", as the villain following through on his threat is explicitly cited by the game's narration as what drives the Saints to ultimately and utterly defeat him. Had he not, pragmatism would have led the Saints to eventually take their partial victory and leave it there.
Most of Awakening 5: The Sunhook Spire involves freeing the enchantress trapped within the title building, which is surrounded by an impenetrable barrier — only to discover that the enchantress erected the barrier herself in order to prevent the goblin villain's warships from landing on the Spire.
In the backstory to Sword of the Stars, mankind's fervent counterattack on the Hivers, who were then in an interregnum and broken up into mutually hostile clans, led to them becoming a united force once again.
Late in Soichiro Irie's route of the Romance GameKiss Of Revenge, Dr. Issei Sezaki realizes that the protagonist is the daughter of a woman who died at Ebisu General Hospital due to a surgical error twelve years previous. He immediately goes to his father, the hospital director, to insist that they owe her a proper apology. Unfortunately, Issei wasn't aware that his father had already asked Irie to check into the protagonist's background, and that Irie knew the details of who she was but was keeping the knowledge of her connection to the death twelve years ago hidden from the director. As a result of Issei's effort to do the right thing, his father is tipped off to the fact that Irie is working against him, giving him the upper hand and almost destroying Irie's plan to make the director step down in a way that will not endanger himself, the protagonist, or the rest of the hospital.
In Super Dangan Ronpa 2, it turns out that the protagonist, Hinata, was the one who smuggled AI Junko into the system and caused the mutual killing to happen on Jabberwock Island. Although he can't remember doing it.
In Quest Fantasy, this is one of the main themes. HERO's mission given to him by the king led to bringing the S O U L into this world, and the game guilt trips you for this immensely, but the prequels reveal that several other protagonists also inadvertently set up his arrival.
The hero party in Dead Island needs to find food for some of the remaining outposts of survivors, and the best place to get large quantities of food is the supermarket, but it's been taken over by bandits who have barricaded themselves inside. A sewer tunnel connects one of the outposts to the supermarket and is the only way in, and the only way to get the guard of that entrance to let them pass is to give him alcohol. In hindsight, maybe letting the only guard on duty get drunk was a colossally stupid idea.
Everything bad that happens after New Guy's first night in South Park in South Park: The Stick of Truth is the New Guy's fault for crashing the UFO and getting the toxic sludge that turns living things into Nazi zombies all over the town. Had he just taken the Anal Probing like everybody else, none of this would've happened.
Rolf's actions in Phantasy Star II end up the case of doing things too well they go out of control.
The team comes up with an idea to put a veil on a kidnapped girl named Tiem to protect her until they deliver the girl to her father (a serial killer with a Freudian Excuse), just to have her killed by the man himself because he doesn't recognize it is her under the veil.
The team investigates the Climate Control Center to prevent a drought caused by a system malfunction. They kill the controller unit, Neifirst, causing the water level to overflow the lake and almost flood the entire planet.
The team defeats Mother Brain, the sole control of Motavia's evolution, to save Motavia from technological domination over men. As the result, they causes the "Great Collapse", which, as described in Phantasy Star IV, the disaster which wipes out 90% of humanity and completely annihilates their civilization and environment. Ouch.
In the obscure iOS game Hack RUN, you end up repelling an alien race that was trying to enslave mankind. Too bad that in the process, you attract a different alien race that will probably destroy mankind once it reaches Earth. Oops.
The first set of missions in Gunpoint has you delete the security footage that shows you were present at the scene of a murder. When you're done with that, the resident Woobie will request that you prove that she did not commit said murder. Here's the thing: The only proof that she was not the only one at the crime scene has been destroyed. By you. And then she commits suicide because she doesn't want to be a burden.
In A Witchs Tale, Liddell releases the Eld Witch, an evil being who was sealed away by Queen Alice thousands of years ago.