- Happens twice in Blood Omen: Legacy of Kain, where you must defeat the members of the Circle of Nine to restore the Pillars of Nosgoth: The first time is in Dark Eden, where the Circle members there summon fellow Circle member and Sarafan leader Malek (who Kain had to retreat from in their last fight) to protect them. Kain responds by summoning Vorador to keep Malek busy while he goes after the other Circle members. After dispatching his original targets, he finds Vordador has defeated Malek for him. The second one is Anacrothe, who escaped from Kain at Dark Eden, only to be dispatched later by Mortanius.
- The Legend of Zelda:
- The Legend of Zelda: Twilight Princess does this in the final dungeon: As Link approaches the tower where the Master Key is being held, he gets attacked by some mooks, but several secondary characters arrive and deal with them from the grounds.
- In The Legend of Zelda: Skyward Sword, Impa presses a switch in Eldin Volcano that activates a bridge so Link can pass over a lava pit.
- No More Heroes: As you prepare to fight ranked #5: Letz Shake, Mr. Sir Henry Motherfucker kills him. Fortunately, you get to make up for it in the end, in an optional final battle with Henry.
- No More Heroes 2: Desperate Struggle: Here you actually get to fight Letz Shake, who kills ranks 11 through 22 off-screen), along with the fights for ranks 5 and 6 (to repay Travis for getting him out of a coma, Henry kills them, gives Travis the ranks, and sends him pictures of the aftermath just to rub it in) He also mocks the player for complaining about it by saying something about there being no way you could have done these fights anyway, because the game is already packed full.
- In Ōkami, Waka restores the Guardian Tree in North Ryoshima Coast for you. Between the fact you get Praise for the ones you restore and how obnoxious Waka is anyway, it's easy to forget it's a scripted event and get ticked off at him for it. You can still get Praise from the tree, however, but it requires an alternate method.
- In Super Metroid, as you make your way into Tourian you come across several enemies the have already been drained by a Metroid, including what appears to be the final miniboss, a third Torizo statue.
- The original Tomb Raider does it deliciously with Pierre - you follow him through, what, four levels, solving every kind of obscure puzzle to open doors, frequently involving destroying permanent fixtures, and then it turns out that he's already there to claim the MacGuffin even though you did all the stuff. How did he get there!? Who knows! Of course, he's the same guy who can ninja-teleport around at will. The remake turns this around: Pierre, rather sensibly, decides to let Lara risk life and limb pulling every damn lever and switch that's in the way of them and their prize, before waltzing in at the very end to claim it.
- Lampshaded in the beginning of Hunted: The Demon's Forge. "Looks like someone helped us out by knocking this tree down."
- In Blade Runner, many witnesses complain that they were already interviewed by another cop.
Beat Em Ups
- In Double Dragon 3 on the NES, Hiruko informs you, after you obtain the second Sacred Stone, that she has the third one. The next level is merely for training purposes before heading to Egypt.
- Fate's story path in Magical Girl Lyrical Nanoha A's Portable : The Battle of Aces has Material-S, Nanoha's Evil Twin, telling Fate that there are more Materials like her with her dying breath. As Fate gets ready to hunt down the remaining Materials, Reinforce Eins contacts her with the news that the troubling activities of this incident had finally ceased with her victory. Fate gets confused for a moment about how that's possible, until Nanoha contacts her too and informs her that she had already defeated the other Materials.
- Then again, Fate's work isn't quite finished yet, as she has yet to defeat the rest of the Dark Pieces and a copy of herself before the incident can be resolved. This trope comes into play in the other characters' routes, as any Dark Pieces or Materials you do not encounter have already been destroyed by one of the other characters you aren't playing as.
- Happens in Samurai Shodown IV if you don't reach the boss in the time given.
First Person Shooter
- Crysis takes obvious measures to avoid Escort Missions as you will either have allies rescue them after you get to them or the hostage will die anyway in such a way that it is not your fault.
- In Halo 3, you have to take out three shield generators on the level The Covenant. After deactivating the first one, the second is brought down by the Arbiter. You still, however, need to take down the third one, because Johnson's team was overrun by Brutes.
- In Metroid Prime 2: Echoes, the Sky Temple in the dark world requires 10 keys to unlock. The first key was already found and put in place by a dead Luminoth warrior laying at the bottom of the key pillar, leaving only 9 for you to find.
- In Metroid Prime 3: Corruption, on the first planet, you are charged with the task of getting 3 generators back online. After you take care of the first one, Rundas, a friendly bounty hunter, sends you a transmission informing you that he took care of the second one and that you should go for the third. He did state he was going after that one before you even started, but, given that side characters in these games, whatever they may say, are generally woefully incompetent at solving any problems big enough for the player to handle, it was a bit unexpected that he actually succeeded.
- In Dynamite Headdy, the boss of the fourth "scene" has been destroyed before you even get there.
- In Monster Party, one of the first bosses informs you that he's already dead before you can fight him. Strangely, the one boss in the game that's definitely dead (fried shrimp stuck on a skewer) has no trouble attacking you!
- In Rayman 2, after flying a pirate ship and saving Globox's babies, one of the babies reveals that he's stolen the fourth and final Mask. The other three were hidden at the bottom of difficult dungeons. This is different in the remake Rayman Revolution where you have to get the last mask the hard way. The Globox Baby gives you the Rain Mask instead.
- Somewhat annoyingly averted in Sonic Adventure. With the "Rashomon"-Style story structure, everyone puts themselves in the spotlight, which means that every time a character is present during a boss' intro cutscene, that character HAS to fight that boss, even if you've already defeated that boss in another character's story. One of the biggest examples is Chaos 4. Since Sonic, Tails and Knuckles witness its transformation, you have to fight him once for each of their stories.
- One popular fan theory suggests a very subtle example of this trope: During Sonic's Sky Deck level, the Egg Carrier's deck is be reoriented while Sonic goes through to the end of the level. However, during Knuckles' run through the level, he flips multiple switches and reorients the Sky Deck himself, and the theory is that it's Knuckles who causes the changes during Sonic's Sky Deck level, meaning that the level shifts required for Sonic to get through the level are already done for him.
- The closest the game gets to this trope is in the crossover of Tails' and Big's stories. Froggy wanders into the depths of the desert, and Big would've no doubt found him and be forced to trek through the entire Sand Hill to catch him. However, Tails notices him first and catches the frog, saving Big the trouble. He still doesn't catch Froggy, however.
- In one level of the Stargate game (for the Genesis), O'Neill had to run around Ra's pyramid destroying all the computer consoles, because one of them was supposed to be special for some reason. When you reach the end of the level, you find Daniel Jackson, who tells you he's already taken care of the right one. He then sends you to kill Anubis (no, not that one) and Ra.
- Downplayed in Super Mario Galaxy, with Luigi searching for stars on his own, but you still need to help him get back to the Observatory, and he gives up after 3 stars.
Real Time Strategy
- World in Conflict does this quite often. In one mission, you actually have to help an ally getting some objectives because you have no ground forces to do it yourself.
Role Playing Game
- Early in Chrono Trigger, Crono gets arrested, and since he's scheduled for execution in three days even if you were found not guilty, most players have him escape from prison, causing the trope to be inverted when Lucca shows up to rescue him. No need, Lucca, it's Already Done for You. On the other hand, if you don't escape in the (relatively short) three days, she does rescue you, and the guards you have to fight on the way out are Already Beaten For You.
- In Dark Savior, depending on how you play the intro chapter, the rest of the game plays out in one of three different ways. In the first one, you go through a set of ancient ruins, solving puzzles to go through each room. However, in the second one, two other characters have passed through right before you, thus all the puzzles are already solved and you can just waltz through. However, this means you don't get to learn the history from the murals, as those are the barriers that move out of the way when you finish the puzzles.
- Dragon Age: Origins: It seems like this is going to happen in the first hour or two. You're told that the Ferelden army has already won two major battles against the darkspawn and are going to finish them off when they come again tonight. Then, when the battle actually STARTS, after you and Alistair complete your mission, Teryn Loghain abandons the king to death, which is how the real game starts off.
- Dragon Quest VI has a kind task you to slay a dragon deep within a dungeon. When you get there, though, you find that Ineffectual Loner Terry subverts the "Ineffectual" part of his trope and defeats the dragon single-handedly. He then proceeds back to the king to obtain the awesome sword that was promised as a reward, making the whole thing a complete waste of time for you, if only it weren't necessary to advance the plot. Later on, this has a reversal: After searching for a Legendary Sword, you finally find its resting place... and Terry promptly appears, rudely shoving past you to claim it. However, before the player has time to get pissed, Terry realizes that the sword is rusted, laughs, and gives the blade to you, actually apologizing for wasting everyone's time. (Apparently, he's never heard of a blacksmith...)
- In the second Drakensang installment, you need to solve some ancient puzzles. Going around, you find, that one has already been solved - by a party of Amazons, whom you now have to fight for your MacGuffin.
- Final Fantasy:
- Final Fantasy IV. At the bottom of The Very Definitely Final Dungeon, two powerful NPCs destroy The Man Behind the Man you've been planning to kill. At least you get to fight his hatred given form.
- In Final Fantasy V, Exdeath sends monsters from the Void to stop the party from collecting the remaining tablets. One of them gets killed by Leviathan before he can attack the party, although Leviathan fights you in his place.
- Final Fantasy VII:
- An early part of the game involves the party breaking out the the Evil Government Headquarters. However, the door is open and the dozen-or-eighteen guards between you and freedom are already devoid of life. Being the bright intellectuals they are however, the party goes deeper into the building instead of taking the time to leave. This, of course, is to find out who had Already Done It For Them. Spoiler: It's Sephiroth. Ok, maybe not so much a spoiler really...
- Later, the party has to destroy the gigantic monster simply known as WEAPON. Good thing that Evil Government Headquarters sees it as a threat too, huh? Nothing like a good old Double-KO to help the good guys out.
- In Final Fantasy VIII, as part of a mission to kidnap the President of Galbadia with an unlikely plan involving switching train carriages around, you're told several times how to avoid detection by the train's red and blue sensors (one detects motion, the other heat, and to avoid being detected by them you have to stay still or constantly move when they're on, respectively). When you get to the part of the train with them, you find they're all broken and you can safely ignore everything you've been told about them.
- Golden Sun:
- The second game starts with you escaping the previous final dungeon (with the Random Encounters turned off, since you're level 1 at that point). You can only access some of the areas, including a chest that previously contained a very high-level cursed helmet. Even if you didn't take it in the first via Old Save Bonus, the chest is empty... except for the lowest-level healing item (how the first game's party missed it, or why they don't have the helmet when they meet them again, is not mentioned).
- You can find an island with a bunch of easily accessible treasure chests... their contents already taken by the inhabitants of the nearby town. However, there are a lot more that aren't accessible without Psynergy.
- One quest in Guardian's Crusade requires you to destroy the Winged Lion monster in order to get the Kuldo Emerald. After battling your way through the dungeon, you find the lion has already been defeated and the emerald harvested. But then if you examine the lion, he gets up to fight again, and you have to defeat him anyway.
- In Hyperdimension Neptunia, when Neptune and her friends take on a lost child quest in Lastation, they reach the final room only to discover that Black Heart has already killed the monster and saved the child. As soon as she spots Neptune, she challenges her to a battle.
- In Neverwinter Nights 2 the player must collect five blessings/abilities from five Illefarn statues, and successfully collects 4, only to find that someone else (who later turns out to be a character who has, up until that point, been a villain) has collected the fifth.
- An implied, villainous example in Paper Mario: The Thousand-Year Door, at one point, you come to a locked tower and must fight a boss at the end of the next corridor in order to get the key. Solving the puzzles within the tower reveals the in the corridor leading to said boss dropping down, revealing the path to the Final Boss. Grodus knew this was coming and sent the shapeshifter, Doopliss, disguised as Frankly, to tell you that Grodus was already inside the dungeon, while in reality, Grodus hung somewhere behind Mario and waited for him to finish the puzzles and open the path to the last room, where he releases the Final Boss from her imprisonment.
- In the original Paper Mario 64, the captured Star Spirit, Skolar, escapes from his imprisonment in Tubba Blubba's castle. Unfortunately he was recaptured by Bow the Boo, who won't give him back to you unless you beat Tubba Blubba, so the escape means nothing (especially since you explore the entire castle in the process, so you don't even get saved the journey to where he was captured originally).
- There was one part in Pokémon Gold and Silver where you team up with Lance to fight Team Rocket and take down their radio broadcast. He takes the left side and you take the right.
- Mixed up a bit in Pokémon Diamond and Pearl, where after the sixth badge is obtained, Professor Rowan sends you and your fellow chosen trainers to Sinnoh's three lakes to protect the spirit trio from Team Galactic. The switch-up lies in the fact that all three of you fail.
- In HeartGold and SoulSilver, Victory Road doesn't have any Trainers in it. The reason for this? Your rival beat them all before you got there.
- In Skies of Arcadia, the fourth Gigas you have to fight for a MacGuffin has already been defeated due to injuries from much earlier in the game by the time you finish that dungeon. Ironically, Plergoth AKA Rhaknam was a Chekhov's Gun that the player expected to fight at some point while the others were more or less just Giant Space Fleas From Nowhere who popped up just to fight you.
- In Tales of Symphonia, it turns out that Kratos has already done much of the legwork required to obtain the materials for the Eternal Ring, leaving only the aionis by the time the party invades the Tower of Salvation.
- Played straight in Treasure of the Rudra: be careful of certain actions that may nerf you out of the best equipment Foxy's Love Whip for example; involves you having to play as Surlent before playing as Sion since the Whip is in the same ruins where a story event occurs in Surlent's Scenario.
- Wizardry: Tale of the Forsaken Land gives an example of this that's also a Guide Dang It moment. An NPC wants an item you have absolutely no way of getting yet. To get it you have to basically clear the entire level in one shot as the recipe is pretty far in, and so is the shortcut back to town. You have to do this to avoid level 3, because if you set foot there an annoying NPC will be waiting and make you play a minigame with them. Winning the minigame gets you the item... but also makes them appear on level 5, where they already did it for you, thereby preventing you from getting the nice reward.
- The World Ends with You is supposed to have quite a few Players also solving the puzzles with you (most of them just seem to be morons who can't even kill the standard Noise). If any Player succeeds at the missions each day, however, any and all survivors will still go on to the next round (this may or may not apply to missions with no time limit). This is surprisingly used twice in the game for plot-related effect, first when Beat and Rhyme taking out a boss you almost killed right before time runs out, and later when Neku loses in Tin Pin Slammer (the objective was to claim the Tin Pin Golem via tourney), but two other Players win it instead when Joshua rigs their game by switching the non-Player's pins for fakes, and once just to Handwave something (a wall is up when approached one way, but down going the other way). Also in the endgame area, you find someone has already killed Taboo Sho for you, and buried him under a pile of his own "artwork". Even though he had no problems kicking your ass and was alive five minutes earlier.
Shoot 'em Up
- Gradius V requires the firepower of another Vic Viper to defeat the final boss. He finishes it off after you destroy your assigned part and leave. You also see him fighting alongside you in his own isolated section of stage 2. However, you time travel to make this happen. You fight alongside your past self. The way you fly your ship in stage 2 will be copied exactly when you return to those spots in the final stage.
- In Star Fox 64 in Sector X, your mission is to invade the enemy base and destroy their secret weapon, only for you to discover the base in pieces when you finally do get there, thanks to the secret weapon malfunctioning.
Falco: Somebody beat us here. It's all gone!
- Inverted in Ten Desires, the thirteenth Touhou game. Mamizou was called by her friend Nue to help defeat the Big Bad Miko. However, turns out the heroines had already defeated Miko when Mamizou arrived. The Mamizou fight the heroines as the Bonus Boss, just because.
- In Descent: FreeSpace you're sent on a mission to destroy some Hammer of Light (i.e. rebel Vasudan) ships, but when you arrive you find they've already been destroyed by the Shivans. Of course, now you have to fight the Shivans.
- In Hitman: Contracts, the first level starts with you strolling through a room of Agent 48s that have already been killed. Justified in that you killed them in the original Hitman, and Contracts takes place directly afterwards.
- The first room of Metal Gear Solid has Solid Snake hiding from guards while waiting for an elevator. The "Plant" chapter of Metal Gear Solid 2 opens with another room where you must wait for an elevator, but in a post-modern twist, Solid Snake has already knocked out the guards.
- In Metal Gear Solid V: The Phantom Pain, Venom Snake can potentially do this to himself if he destroys a certain communications post in Free Roam mode. When he is assigned the mission to destroy it, your team realizes it's already been dealt with and you immediately receive a Mission Complete.
- Resident Evil Outbreak is an instance when this trope is actually a welcome in-game element. The final level of the first game is huge, and requires you to find and combine two key items located in two different areas of the level. You can choose which area you wish to visit first, and nine times out of ten, you'll return to the main building to find that one of your AI partners has already visited the other area and retrieved the second item for you.
Turn Based Strategy
Wide Open Sandbox
- Literary example: In The Keys Stand Alone: The Soft World, the four travel to Boidan Mine in the hopes that it will contain a powerful amulet that Ringo needs badly. However, when they arrive in Boidan Valley and Ringo mentally scans the area, he immediately sees six sets of hoofprints and realizes that a group is already in the process of raiding the mine. This forces the Actual Pacifist four to figure out how to ascertain whether the “mine-robbers” found the amulet, since they won't just beat up the party and take their stuff. Hilarity Ensues. No, they didn't have the amulet.