Video game magazines and websites usually does this when covering sequels as they always assume that the reader has played and/or beaten the previous game(s). The very first sentence and/or paragraph of a preview/review will usually spoil a major plot twist or the ending(s) of the previous game(s). For example, Game Informer's preview of Metal Gear Solid V spoils the events of the previous prequel games in the Metal Gear series.
Aliens: Colonial Marines, by virtue of being a P.O.V. Sequel to the 1986 film, spoils the climax of the movie (and its offscreen result) by necessity. The Hadley's Hope colony on LV-426 was almost completely destroyed due to an atmosphere processor explosion caused by the main characters in the film.
The Amazing Spider-Man (2012) gets this in spades. In addition to being released a week before the actual movie was released in theatres, the game is a sequel to said film and spoils several plot points in its opening mission. This includes the Lizard's tear through the city, Dr. Connors being locked up, Connors' engineered virus/antivenom and Captain Stacy's death.
Happens at the last minute in Another Code: R, the sequel to Another Code: Two Memories ("Trace Memory" in America). The plot of Two Memories revolved around the murder of Ashley's mother, Sayoko, and the big reveal at the end concerns who her murderer was. Although R talks about the murder of Ashley's mother right from the start, as well as the fact that her killer recently got found out, they step-around revealing who her killer was. Her killer even gets their own profile, where they are identified as the "Sayoko's killer", but the name is kept as "???" and they are given the generic "unseen male" silhouette. That is until right near the game's climax, where Bill Edward's identity as the killer is very bluntly dropped into conversation, as though they had given up with trying to keep first game unspoiled.
Ubisoft quickly learned that when you have a prolific franchise like Assassin's Creed whose entire Framing Device is a massive spoiler, you can't keep the cat in the bag for long. The existence of the Animus and the real protagonist, Desmond Miles, was kept heavily under wraps during production of the first game, even after Kristen Bell accidentally leaked part of the plot in an interview. Since then, the developers have been surprisingly coy when dealing with the modern-day plotline in each game; in previews they'll mention Desmond and the Animus every now and again, but all but the bare essentials of Desmond's plotline in each game is a tightly-guarded secret, with the developers only ever showing gameplay from inside the Animus. Former franchise director Patrice Desilets even got in on the act by teasing that Brotherhood's cliffhanger ending almost made Nolan NorthRage Quit the studio.
Assassin's Creed IV: Black Flag would be the first in the main game series to not follow Desmond Miles, with the new Animus operator being an anonymous researcher at Abstergo Entertainment, but a story mission reveals that Desmond Miles wasn't a consensual "Sample 17" donor... because Abstergo simply took the DNA samples from his corpse soon after his death at the conclusion of Assassin's Creed III.
That the Player Character is a bhaalspawn and the half-sibling of Imoen and Sarevok was considered by many as a huge twist in Baldur's Gate. That is spoiled in the intro and trailers of the sequel.
Batman: Arkham Knight: The Game of the Year edition gives you some extra skins for the Arkham Knight, which reveals his identity as Jason Todd/Red Hood before you even start the game.
BlazBlue. Kokonoe's a catgirl, Ragna and Jin are brothers, Hakumen is future!Jin, and Hazama is Terumi. The first two barely count as spoilers, since they're both casually mentioned in the Fourth-Wall Mail Slot. The opening wall of text for Hazama's Arcade Mode route in Continuum Shift reveals his status as The Man Behind the Man and Continuum Shift II has a new opening FMV that shows Noel turning into Mu-12. Likewise, Chronophantasma wastes no time in "reminding" players that Ragna's kidnapped little sister Saya is the Imperator of the NOL, though this has the effect of covering up an even bigger twist, one that players might only guess in advance if they were privy to sidestories and/or XBlaze.
In Borderlands 2, most of the DLCs canonically take place after the main storyline is completed, but can be played during it if the player is prepared enough. As a result, large chunks of the story are spoiled, especially in the Headhunter DLCs. Upon starting the fifth Headhunter DLC, "Son of Crawmerax", you'll hear the three Vault Hunters from the first game spoil the following: that Handsome Jack is dead, Mordecai is training a new bird to replace Bloodwing, and Roland is nowhere to be found. Likewise, Tiny Tina's Assault on Dragon Keep spoils the fact that Roland is dead and the group are struggling with how to break the news to Tina.
Invoked by BoxxyQuest: The Gathering Storm. New players are encouraged to start with this entry instead of seeking out the (dated and amateurish) prequel, so all the relevant plot points are laid out right at the start, by way of a text file included in the download. Pieces of the first games ending are even shown in this ones opening cutscene, including Boxxyfan's defeat and Catie's coronation.
In the second half of Brütal Legend, Ophelia undergoes a FaceHeel Turn and commands the Drowning Doom. Of course this was spoiled quickly by the game's commercial, magazine coverage, the demo, and the Drowning Doom being a playable faction in the game's multiplayer.
The first trailer for Call of Duty: Modern Warfare 2 blatantly spoils the fact that the death of Imran Zakhaev (the Big Bad of the first game) is what directly causes the antagonist of the sequel, Makarov, and his splinter group to seek revenge.
Likewise, Modern Warfare 3's trailer spoils the fact that Vladimir Makarov is still alive and well after the events of the second game, and that tensions between Russia and the U.S. have escalated into all-out warfare. The cutscene before the prologue also blatantly spoils the fact that Shepherd was the Big Bad of the second game and Soap and Price were the ones who killed him.
The WiiWare version originally contained some extra playing modes in addition to the original game, none of which require any sort of unlocking. So you can spoil the boss fights by playing the Boss Rush game before the main game, or you can spoil the existence of a character who's introduced one-third into the game by playing "Curly Story" first. The modes has since been patched so that you need to unlock them first in order to play them (as with the future versions of the game).
The Cave Story 3D box art makes it quite obvious that the main character is a robot.
The main character's name is "Quote". This was originally a secret that was only revealed on the very hard to unlock path to the Golden Ending, but it's now being used casually by official sources like it's nothing. Quote even appears as a playable character in the fighting game Blade Strangers and the Nintendo Switch fighting-puzzle game Crystal Crisis with his name in full display, so the spoiler is pretty much impossible to avoid. Admittedly, talking about the character otherwise would be hard, since he has No Name Given until The Reveal.
In the DS version of Chrono Trigger, the dojo section features pictures of the various techs in action. This is fine as they're only unlocked after you learn them. However, some of the first techs unlocked show Magus in your party, who won't join you until near the end of the game. The SNES version's manual also contained a profile on all recruitable characters, including this surprise character.
Crysis 3: The trailers freely call the protagonist Prophet. Alcatraz? Who's that?
The Saw Chapter DLC for Dead by Daylight spoils several plot points from the first three Saw films: first, that John Kramer is Jigsaw; second, that Amanda is his apprentice, not his victim; and third, that Kramer, Amanda, and Detective Tapp are all dead. Given that the DLC was released shortly after the eighth film had just left cinemas, the developers likely assumed it would be a case of It Was His Sled.
Deadly Rooms of Death: The title of The City Beneath spoils a surprise at the end of the previous game, Journey to Rooted Hold. The title of the next game, The Second Sky, does the same for the ending of The City Beneath.
The marketing and trailers for Dead Space 2 assume that the viewer knows that Isaac Clarke is the only survivor of the events from the first game, and that every other character from the first installment (including your girlfriend Nicole, who is now showing up as a hallucination) has died). Likewise, the Severed DLC mission spoils the fact that Gabe and Lexine Weller are the only ones who survived the events of Dead Space: Extraction.
The History of DMC video unlocked by beating Devil May Cry 4 likewise gives away all of the spoilers and plot twists from the first three games.
Casual screenshots of Disgaea 2: Cursed Memories will spoil an event that happens to someone in Disgaea: Hour of Darkness.... Namely, that Laharl isn't a complete asshole, and airheaded Love Freak ultra-pure Angel trainee Flonne has fallen from grace and become an airheaded Love Freak ultra-pure Devil trainee. And don't even try playing it if you mind spoilers, because the intro movie reveals the same thing. Also, Prinny Kurtis is part of the storyline.
The opening of Disgaea 3: Absence of Justice spoils this too. So does merely shopping at the Rosenqueen store in real life. In fact, it's hardly worth tagging the spoiler anymore.
When playing La Pucelle, a spiritual predecessor to Disgaea, that there is a pair of secret scenes where Priere becomes a Demon Lord and Demon Overlord is technically a spoiler. However, with La Pucelle: Ragnarok, the remake of La Pucelle, Priere's demon form is right on the cover. Of course, it's now a full route, not merely an ending. And she has appeared in four later NIS games as a "secret" character, and another as DLC, in full demonic glory no less, it's not much of a secret to anyone with an interest in their games. On top of that, many secret characters aren't. It's practically expected that the major characters of previous Disgaea games will appear, even in remakes, plus Asagi since Makai Kingdom, plus a splattering of others. It's just a question of which characters from those games will appear.
Mostly averted with most franchises/movies represented in Disney Infinity (such as The Force Awakens for example) except in moments that are very much It Was His Sled moments. (Such as Syndrome.) However, there are two big moments (relating to Zootopia and Finding Dory) where it's played straight: A Zootopia based Power Disc enables Nick Wilde to wear the police officer outfit he gains at the very end of the movie, and the Finding Dory Play Set is clearly set after the events of the movie itself, thus former Marine Life Institute residents Destiny, Bailey, and Hank are already living at the Great Barrier Reef with Nemo, Dory, and the others.
The NES version of Double Dragon III: The Sacred Stones changes the plot from the Japanese version by revolving around the Lee brothers trying rescue Marian once again, which spoils the fact that she is restored back to life at the end of Double Dragon II, since that game's plot revolved around aveging her apparent death at the hands of the Shadow Warriors.
The entire prologue of Dragon Age II spoils the first several hours of the first game, such as the loss of most of the Ferelden army at the ill-fated Battle of Ostagar, Loghain's betrayal and the death of King Cailan, as well as the destruction of Lothering at the hands of the Darkspawn horde.
The entire game can be considered this and a First-Episode Spoiler due to the Framing Device. The opening states outright that Thedas is currently on the brink of a World War and the Chantry has fallen to pieces, due to something that the Champion and their friends did. Varric then proceeds to explain how Hawke became the Champion of Kirkwall and How We Got Here.
The trailer also revealed the death of the Viscount and that Hawke will eventually be forced to fight the Arishok. What it doesn't give away is that this happens 2/3 of the way through the game and isn't remotely the end boss.
In Dragon Age: Inquisition, it's generally not considered a spoiler that the Player Character's title is "The Inquisitor", and players openly call their characters by that title in spoiler-free discussions, even though, story-wise, the player character only receives that title after the first act, after Corypheus destroys Haven and the Inquisition moves to Skyhold.
Many works parodying or otherwise discussing EarthBound reveal the final boss's weakness.
The Elder Scrolls: The blurb for Daggerfall on Bethseda's site and in the Elder Scrolls Anthology mentions the Numidium, and tells you its backstory. This is information you don't find out until almost the end of the main quest. During the original release, the only thing the player knew going in was that King Lysandus was not at rest, and that a letter from the Emperor had gone astray. note The spoilers aren't even accurate either; they state the Numidium has recently been unearthed in the Iliac Bay region. It's Tiber Septim's Totem that has been unearthed; the Numidium was reassembled at some point in the past (presumably somewhere in Cyrodiil) after the Blades had tracked down all of the fragments.
Despite being a remake of the first game in the series, Etrian Odyssey Untold has late arrival spoilers for the series. The intro features scenes of futuristic technology, and early on in the story mode you visit a ruined high-tech facility, and Raquna reveals she's from Ontario — which is heavily implied to be exactly where it sounds like. The fact that series is set in a post-apocalyptic future Earth was originally a twist revealed extremely late in the first game.
In Etrian Odyssey IV, there is a secret class available in the last quarter of the game, the Imperial class; the name of the class is a reference to the Empire of Yggdrasil where people of this class come from and which is the highly-advanced aggressor country in opposition to the civilizations and races of the other three lands. Etrian Odyssey Nexus has this class available to recruit right from the start, with their position in the class list (classes are organized by debut game) making it clear which game they're from.
Fallout 2's manual included The Vault Dweller's memoirs, which was essentially a spoiler and walkthrough for the first Fallout.
The opening cinematic for Final Fantasy IV DS just assumes that you already know the whole plot, and it spoils, among other things, that Cecil has to fight Kain at one point, that Cecil becomes a paladin and fights against his own inner darkness, that Kain is intensely jealous that Rosa is with Cecil, that the Tower of Babil is actually the storage place for a giant mech that can destroy the world and the Red Wings and Dwarves are going to fight it, that Rydia eventually returns and can even summon the Leviathan that seems to kill her, they reveal the final team including Kain, and finally as the coup de grace they reveal the Lunar Whale that takes you to the moon. Of course, this is a grand tradition with the game; the original American release revealed in the instruction manual that FuSoYa would be joining your party, and was from the moon. Also, when you meet Jammingway and he shows you the music player; the character playing (and adding lines of narration to) the music is Edward, who at that point in the game, is presumed dead. If you haven't played the game before and don't know that he's alive; this is kind of a giveaway, because using a dead character for the music player would be... kinda...
Final Fantasy VII: Crisis Core stars a protagonist who is a spoiler. His existence, appearance and role are almost entirely unknown until Cloud untangles his Tomato Surprise, very late in the game. Mails sent to this protagonist casually drop facts like SOLDIERs being implanted with Jenova cells (a major spoiler in the original, since it explains that Cloud's reason for wanting to hunt down Sephiroth isn't simply revenge), and - well, when Cloud shows up and he's a Shinra grunt rather than a SOLDIER First Class, that twist is ruined for you.
The truth about Cloud was already prematurely spoiled in 1999, in Ehrgeiz: God Bless the Ring, where his alternate costume was a Shinra infantry uniform.
Also, Zack dies at the end, which is why he's not in the main game. And if you have played the original, you know Zack dies, which puts both games in the uncomfortable situation that any of the two games spoils the other, so no matter in which order you play it, you're still screwed.
The ending of Final Fantasy XII left you hanging right up until the moment before the credits on whether or not Balthier and Fran die in a heroic act. Unfortunately, shortly before the game was actually released in North America, there was already a trailer for Final Fantasy XII: Revenant Wings (the Nintendo DS sequel) circling the web which revealed them to be alive and well. Any English fan who saw the trailer before reaching the end of the first game were therein stolen any and all suspense on the reveal that Balthier and Fran lived after all.
Their survival was hinted by Penelo, who pointed out that their airship couldn't have been stolen if the original owners were retaking it. They also received a letter presumably from Balthier and Fran, as it included Ashe's wedding ring that Balthier 'looted' from her (which he said he'd return if he found something of greater value).
In Final Fantasy XIII one of the main goals of the main characters is to find a way to free Serah from her crystalline form. Given she is the prominent main character in the sequel, knowledge of the second game ruins any suspense.
One of the issues in Final Fantasy XIII-2 was whether there was a way to release Vanille and Fang from the crystal spire, especially after it is discovered to be crumbling. Vanille shows up in the first section of the final game.
For the PC port of Final Fantasy XV, a lot of the cover art focuses on old bearded Noctis. How he comes to be a middle-aged bearded dude is one of the final plot twists in the game - he spends 10 years sealed in a crystal to gather the power to kill Ardyn.
Promotional material for Fire Emblem: Radiant Dawn seemed to consider that the Black Knight's identity was common knowledge, even though the fact that he's Zelgius is not revealed until the start of Part IV.
Fire Emblem Heroes naturally has a lot of this, due to featuring characters from across the entire series who often allude to their own games in dialogue.
From Genealogy of the Holy War: Seliph mentions his father's death, Julia is identified as his half-sibling (which was a major reveal in Genealogy of the Holy War but Heroes has the two fight together in a Paralogue called Family Bonds), and it is heavily implied something tragic happens to Eldigan.
From The Blazing Blade: Zephiel is the nihilistic villain he was in The Binding Blade, Matthew's dialogue references Leila's status as The Lost Lenore, and Ninian is actually a dragon.
From Radiant Dawn: Sanaki appears in the Sibling Bonds paralogue (though her sibling wasn't released until nearly a year later and is never directly identified as such, the fact that she even has a sibling isn't revealed until late in the game). The Black Knight's identity is a double subversion; his first appearance was under the Black Knight identity and didn't spoil anything, but his second appearance is under his real name of Zelgius, with his Black Knight weapon and armor sans helmet.
From Awakening: In addition to the Lucina example from Smash Bros above, Robin is shown to be the intended vessel for Big Bad Grima.
In Fire Emblem Gaiden, Alm learning that he's actually the long-lost prince of Rigel was a late-game plot twist. However, the DLC level in Fire Emblem Awakening that allows you to recruit Alm is pretty blatant about it. The remake, Echoes: Shadows of Valentia, also includes loads more foreshadowing than the original version did. This is less of a deal for Japanese players who might have played Gaiden, but for western players who may not have, it severely lessens the surprise at the end.
The fact that the animatronics are haunted by children who were murdered by a Serial Killer was originally a well-hidden secret, but this got focused on more and more as the series went on.
The existence of Foxy and Golden Freddy - neither one is shown in the first game's trailer and are effectively surprises for players flying blind. Later games don't even try to pretend the two (particularly Foxy) don't exist, though Golden Freddy still isn't advertised even as his significance grows. This also applies to BB - while he does appear in the second game's trailer, he looks more like a decorative statue than a surprise animatronic, but later games aren't so coy regarding his true nature.
The end begins! The end begins! The end begins! The end begins now! Betrayal, rage, rage! The end begins now! I will kill him! I will kill him! Patricide! Genocide! I will kill them all! Olympus shall fall!
The fact that Kratos himself killed his wife and daughter was a major revelation halfway the first game as we were lead to believe that Ares did (Though Ares actually planned this murder). This is casually mentioned at the beginning of all the next games including prequels.
Gwent offers two divergent possible solutions to the quest to determine the ruler of Skellige, showing both Cerys an Craite with a suite of Queensguard and Svanrige an Tuirseach's flavor text naming him king.
Throughout the development of Halo: Combat Evolved, the existence of the Flood was kept a secret. Afterwards, they were still considered spoiler material, and magazines avoided directly referring to them. Then the second Halo novel, adapting the original game, was called Halo: The Flood. And just to drive the point home, the cover of said novel was a picture of Master Chief fighting the Flood.
The confirmation that Halo 4 would feature Master Chief spoiled the fact that Master Chief didn't really die at the end of Halo 3, which can be seen after 3's end credits.
The video game conventions the player takes no notice of initially in Haze are supposed to be Painting the Medium, as it turns out they're actually being implemented on the Player Character. This Plot Twist would be more of a surprise if it hadn't been spoiled by every single preview of the game after a certain point. Those frathouse manchildren who are your comrades in arms? They're actually on drugs, and literally can't register the death and destruction they cause.
A teaser trailer for Jet Set Radio Future (circa 2001) had text reading "DO YOU KNOW?" and then displayed the JSRF logo as Potts (in his anthropomorphic, playable character form) dances around in the background. People who did not know that he was an unlockable in the first game and saw this trailer were most likely thinking, "Why is the dog on rollerblades and dancing?"
JoJo's Bizarre Adventure: Eyes of Heaven spoils pretty much the entire series, including parts that have not yet been covered by the anime adaptation. Considering how said anime is the source of much of the series' modern popularity, and a very large portion of fans have not yet read the manga, this blocks a large portion of the fandom from being able to fully enjoy the game. For example:
The first 8 chapters of the story mode are set during or after on of the parts, and open with a recap that spoils most of what happens in that part, including character deaths. The second chapter of the story mode is the part 5 chapter, a part which is not yet adapted, meaning that an anime-only watcher can't even play the story past chapter 1 without seeing major spoilers.
Just looking at the character select screen can spoil major plot twists:
Kira Yoshikage changing his appearance using Cinderella is something that happens more than halfway into part 4. His second identity takes up a separate character slot.
The mafia boss Diavolo's name and appearance are a mystery until near the end of part 5. Hovering over his icon will spoil both of these things.
The fact that Pucci has an evolving Stand only comes up towards the end of part 6. It's pretty much impossible to explain the playstyle of "New Moon Pucci" without spoiling that.
Diego from an alternate dimension, with The World for a Stand was the final battle of part 7 and a huge Wham Episode.
Due to Kingdom Hearts: 358/2 Days, if you didn't know that Roxas is Sora's Nobody, and that he was a member of Organization XIII, then you're in for a bit of a shock.
Chain of Memories (which was released for Nintendo's Game Boy Advance) assumes that the player has played the original game (which was released for a rival console system, namely the Sony PlayStation 2). In other words, this trope comes into play especially, if a player didn't have a PS2, but did have a GBA and was interested in the series.
Later on, Kingdom Hearts II spoils the events of Chain of Memories, which did have a PS2 re-release (Except in Europe)... after KH2 came out. In other words, Square-Enix really wants you to know this already.
The trailer for Dream Drop Distance spoils Birth By Sleep. Specifically, it shows Vanitas unmasked. Those planning on playing Birth by Sleep should avoid watching the end of the trailer. The game itself also manages to contain one for another game. You see, the first world you visit features characters from The World Ends with You. Including Joshua. Story cutscenes don't directly state, but very heavily imply, that he's a Physical God. Which is, like, you know, the biggest plot twist in TWEWY! Granted, most of it doesn't make sense unless you've played the original game, but even if you haven't, it's pretty obvious anyone who sprouts angel wings and flies away probably isn't a normal human teenager like their appearance suggests.
The Twist in Kingdom Hearts II was that the villain from the first game wasn't who he said he was, and it turned the entire series on his head. Ten years after the fact, good luck trying to get into the series without someone talking about it nonchalantly. While he's still referred to by his fake name, nothing in the games even try to cover it up.
If you haven't played Dream Drop Distance on 3DS, don't look too much at the HD 2.8 cover. The cover groups all the protagonists of the three games - Aqua and Mickey for 0.2; the Foretellers for Back Cover; Sora, Riku, Donald, Goofy and Axel for Dream Drop Distance. This obviously spoils that Axel, or rather his human counterpart Lea, joins the good guys in DDD.
In The King of Fighters series, no game after '97 does much of anything to hide the fact that Yashiro, Shermie, and Chris are in fact Orochi cultists (e.g. '98 referring to them as the Orochi Team, rather than New Faces Team or Band Team).
Left 4 Dead 2 revealed in The Passing DLC that Bill died on their way to Georgia. When The Sacrifice DLC came out, along with a comic that shows the events that took place before and during The Sacrifice, people that didn't play The Passing were quite surprised to see Bill getting Killed Off for Real, especially so considering The Sacrifice came out for both games, but The Passing was only for 2.
The Legacy of Kain series spoils itself in the openings. This is especially the case for the opening cinema of Soul Reaver 2.
The Legend of Heroes: Trails of Cold Steel ended on a massive cliffhanger that revealed several characters were Evil All Along and drastically altered the status quo. Since the sequel begins almost right where the first game ended, watching the trailer for the sequel, or even looking up any information on it period, will spoil practically the entire first game. And the first game's extremely well-hiddenBig Bad is right there on the back of the sequel's box.
It is revealed in The Legend of Zelda: The Wind Waker that Tetra is actually the titular Princess Zelda. The Legend of Zelda: Phantom Hourglass being the direct sequel, this information is shown in the opening cinematic. The Legend of Zelda: Spirit Tracks, despite skipping two generations, does still manage to ruin this twist for anybody who hasn't played The Wind Waker yet, thanks to Tetra building a massive stained glass window, depicting herself (in Pirate-garb) in the thoronation-chamber and to Zelda praying to Queen Tetra herself, clearly saying her civilian name, before the Final Boss Battle. At least's it's not as obvious as in the Phantom Hourglass case, as both of this instances are easy to miss if you're not familiar with the character Tetra yet.
The Legend of Zelda: Twilight Princess HD puts spoilers right on the front of the box: the appearance of Ganondorf, as well as Midna's true form. The latter also showed up in the manual of the original version of the game. Oddly, the HD box art doesn't even have Zant on it.
Some editions of The Longest Journey include a trailer for the sequel, Dreamfall on the disc. If you watch that trailer it makes it pretty obvious that April won't become the next guardian at the end of the first game.
The PlayStation remake of Lunar: Silver Star Story is horrible about this. You should have absolutely no doubts in your mind as to who the Goddess is and what the Magic Emperor does with her, since Dark Althena is right on the box. It kind of sucks the suspense out of the plot. It does not help that the game allows you to play Alex's Ocarina to hear the soundtrack, one of the BGMs blows the identity of the Magic Emperor by using the full name of the track, "Magic Emperor Ghaleon".
For the remake of the sequel, Lunar: Eternal Blue the characters section of the manual labels Nall as ??? to avoid revealing his identity as the dragon companion from the first game, in human form and only shows a silhouette of Ghaleon. However, the standees that come with the game feature all the characters with their names labelled at the bottom, including Ghaleon and Nall.
Back before Infinity came out, the idea that the protagonist in Marathon might be the 10th Mk. IV cyborg was seen as a wild and hotly contested piece of Fanon by most players. Now, of course, many descriptions of the game refer to him simply as "the Marathon cyborg", even though this still hasn't been made entirely explicit by the game itself.
Mass Effect 2's marketing runs on the fact that players are aware that Shepard destroyed Sovereign in the first game (which ruins the impact of Shepard's supposed "death" and reappearance). Likewise, the Xbox Live Marketplace spoils a DLC mission titled "Normandy Crash Site". Wonder what that's all about?
Mass Effect 3's trailers showcases a number of characters from the previous games, including ones who took part in the titular suicide mission of the previous installment (including Garrus, Tali, Jacob, Miranda and Legion). Ashley/Kaiden also show up front-and-center in the trailers, making the whole sequence where they're paralyzed by the Collectors in ME2 (and eventual rescue) a non-surprise. To make things worse, the Xbox Live Marketplace spoils the fact that you can recruit a Prothean squad member in the "From Ashes" DLC pack. And the existence and impending return of the Reapers, which was a fairly shocking twist in the first game when Shepard speaks to Sovereign, is more or less the entire conflict of the third game, shown front-and-center. The fact that Sovereign is a Reaper is The Reveal of ME1, but someone who has caught as much as a glimpse of ME3 promotional materials will immediately figure out the truth about Saren's alleged geth dreadnought.
To go with the aforementioned XBLM spoiler, the existence of Javik in the third game is itself a spoiler for the second. Once you've seen him, the fairly major reveal that Collectors are Reaper-mutated and controlled Protheans is beyond obvious.
In the Mega Man Battle Network series, it is an open secret that Baryl, the Big Good of Team Colonel, has joined the WWW between the fifth and sixth games.
The Metal Gear franchise has many examples of this:
Metal Gear Solid both uses and averts this. Snake explains to Naomi about how he and Gray Fox battled each other to the death in Metal Gear 2: Solid Snake, which was a huge spoiler (and particularly infuriating for fans considering Metal Gear 2wasn't released outside of Japan at the time, unless they played the fan-translation). However, the game also averts this by not mentioning the bigger twist involving Gray Fox in that game: the fact that he had been the real identity of "Snake's No.1 Fan", the person who fed him anonymous information, and Frank Hunter, Natasha Marcova's fiancee. This is probably because Metal Gear Solidrepeats that twist to a tee, even with the same character: "Deepthroat" is Gray Fox, who signs off from his first call after calling himself "one of your fans".
In Metal Gear Solid 2, despite the promotional material and packaging hiding the twist, the manual has to tell the player (by necessity) that Snake is not the only playable character. The game also runs into All There Is to Know About "The Crying Game" territory - it's taught in game design courses and referred to by almost everyone who plays the game as being fourth-wall breaking, insane and incomprehensible (thereby spoiling most of the shock value to new players).
The main selling point of Metal Gear Solid 3 is that it chronicles Big Boss' Start of Darkness. It was originally meant to be a reveal in the first Metal Gear, but now doesn't need to be spoiler-marked.
In Metal Gear Solid 4, Snake's role as the main character spoils one of the plot twists from MGS2. In addition, the reason behind Snake's attempted suicide at the end of the game spoils the whole plot twist of FOXDIE in the original game for anyone who's paying close attention. Also, his rapid aging spoils the Les Enfants Terribles project.
The very first trailer for Metal Gear Solid V: Ground Zeroes revealed the fact that Paz Ortega Andrade wasn't as innocent as she seemed. This was the major twist of Peace Walker.
The marketing for Metal Gear Rising: Revengeance will have anyone who didn't play MGS4 asking, "Wait, why is Raiden a cyborg?" It also spoils the "former child soldier" plot for those who didn't play MGS2.
Metal Gear Ac!d casually drops colossal spoilers for the canonical series in the names of character card abilities, like Fortune's ability ("EM Device", which lets you dodge bullets) and Liquid Snake's ("FOX-DIE", which boosts your abilities ridiculously for a short time before killing you). Even so, the first game was comparatively gentle compared to the second, which had an upgrade mechanic which would boost your card's abilities but virtually always rename it to the character's real identity if there was one ("Solid Snake (MGS1)" becoming "David", "Alice Hazel" becoming "No. 16"...)
During the Mortal Kombat: Deadly Alliance - Mortal Kombat: Armageddon days, it was treated as a huge spoiler that Liu Kang dies, and that his body is resurrected by Raiden. In Deception trailers and walkthrough guides, his zombie appearance was for the most part well-hidden and omitted. Come Armageddon, and he is seen near the end in the game's intro. While it CAN still surprise a player (as he is given a proper entrance when he confronts his murderer, Shang-Tsung) the cat is out of the bag,
Likewise, Raiden becoming corrupted. Deception's intro ends with his Taking You with Me attempt, and he is implied to have been Killed Off for Real... until he is unlocked, and we see that he had become a Dark Messiah. While this was not as hidden as Liu Kang was, this spoiler is also casually shown in the subsequent games, including the intro of Mortal Kombat 9, that will leave plenty tilting their heads at why Raiden had suddenly become evil, and is also an alternative costume piece for 9 and Mortal Kombat X as nothing more than for aesthetic reasons. That is, until Dark Raiden returns to the fray at the end of X as a surprise, but time will tell if this too would remain a Late-Arrival Spoiler or not.]
In the first game in the Myst series, the central plot discoveries are that Atrus is still alive, and both of his sons are evil, so contrary to the implied setup you need to Take a Third Option and help neither of them. If you read the back of the second game's box prior to playing the first game, you will already know #1, and taking even a cursory look at any publicity for the third or fourth games will almost certainly tell you #2. Justified in that the later plots build directly on these points, and there would be virtually no way to advertise without spoiling them, but the functional result is that every major plot point in Myst will already be known to you if you've read the blurbs for the sequels.
Mystery Case Files: Rewind, as a nostalgic revisit of the entire Mystery Case Files franchise, spoils quite a bit of the earlier games in the series, but special mentions go to the return of the quite unexpected Big Bad from Huntsville. Therefore, the game manages to spoil the ending of the first game of the series sixteen games and thirteen years later.
The Neptunia series have a character named Yellow Heart which in the game she is introduced in is revealed to be Peashy. She feel into this trope when she was announced as a playable character in Re;birth1.
Arfiore was always a notable recurring boss throughout this series yet is also this after she is revealed to be the Deity of Sin Her DoS form is one of the biggest spoilers of the game yet is completely revealed in later games outside Re;birth1.
Neverwinter Nights 2: The spirit meter mechanic of Mask of the Betrayer is explicitly stated by the manual to be a spoiler; this doesn't stop every review from detailing it. It didn't stop Atari's PR Department from making it a selling point either.
Nights of Azure: Those who want to play the first game unspoiled may wish to avoid all promotional material related to the sequel, as it heavily features former main character Arnice after she became the Nightlord, which spoils most of the endings of the previous game.
Goro Akechi is the one who sells Joker out during the Niijima's Palace heist. This was widely speculated to be the case even before the game came out, so no-one was surprised when datamines of digital preloads of the game revealed it to be true. Later merchandise, including a set of GraffArt merchandise based on key scenes for each of the Phantom Thieves, as well as the reversible cover for Volume 11 of the game's Animated Adaptation, make no effort to hide that Akechi is also Black Mask.
In a subtle example, Akechi isn't present in a fair amount of promotional material for the game, which was done to hide that he joins the Phantom Thieves later on despite his public dissaproval of them, yet he's present on the box art and the game's title screen. The fact he's also playable in Persona Q2: New Cinema Labyrinth doesn't help matters either.
As for Persona Q: Shadow of the Labyrinth, Teddie is happily frolicking through trailers in his human form. Blonde, blue-eyed Bishōnen Teddie was a spoiler on-par with Naoto's reveal in the original game, to the point that the game's opening even attempted to disguise the fact that Teddie was going to be a fully-fledged party-member even though the opening demo most definitely didn't), but in Persona Q, it is treated as an incidental quirk of his character.
In the Fighting GameSpin-Off, Persona 4: Arena Ultimax, every character from Persona 3 is playable, except for the protagonist and Shinji, since both of them suffer Plotline Deaths during 3's story. The story mode also blatantly states who the murderer was in Persona 4 on several occasions - the only way they could have given it away any further was if said murderer managed to be a playable character in the game. Oh, wait.
Said murderer is also a DLC character in Persona 4: Dancing All Night. While the game doesn't quite spoil their identity, their playability ought to raise some alarm bells that they're not all they seem at first glance.
It was impossible to see any commercials for Pokémon Platinum that didn't spoil Cyrus's status as Team Galactic's boss or the fact that he tries to summon a legendary or two. Guess they assumed that everyone had played Pokémon Diamond and Pearl...
Once the official website's Pokédex updated to include the Pokémon from Pokémon Sun and Moon, it made no effort to hide the relationship between Cosmog and Solgaleo/Lunala. For that matter, it also didn't hide the fact that the Ultra Beasts are part of the Pokédex despite the game building them up as separate creatures from Pokémon entirely.
The official website for Pokémon Ultra Sun and Ultra Moon not only completely spoils the twist of Nebby evolving into the mascot legendaries, but also spoils the twist that Lusamine is the Big Bad of the original Sun & Moon games.
The Direct trailer also gives away the Ultra Beasts being normal Pokemon, if the Pokedex in the site didn't give it away already. Note how the title for UB Burst and UB Assembly appearing is "New Pokemon?"
Nintendo seems to feel that anybody interested in buying the Sky edition of Pokémon Mystery Dungeon: Explorers should already know the parts of the plot from Time/Darkness. This goes to the point that they include an animated special that spoils the entire game up to that point as a pre-order bonus. Add to this the clear hints in the commercials and the info on Sky's website and it's all over.
Valve's Marketing Team spoiled the fact that you are hundreds of years in the future in Portal 2, and that GLaDOS is still alive, and back online. Anyone who hasn't played the original game won't be surprised at the twists in the original game.
The mere fact that GLaDOS is a self aware machine is a spoiler. You don't learn until late in the first game that the malfunctioning, seemingly helpful voice helping you is a maniacal killing machine. Yet the commercials for Portal 2 were spoken by GLaDOS.
The opening cutscene of the Portal level pack in LEGO Dimensions casually mentions the fact that Wheatley nearly destroyed Aperture Science in Portal 2; a fact that is constantly referred back to as you go through the levels. The game does show some mercy, however, since it doesn't tell you how he came close to destroying the facility, though Wheatley does mention he's sorry for attempting to "bump Chell off" at one point.
There's another minor spoiler in that game's Portal 2 Adventure World, which features the wheat field that Chell sees after escaping Aperture.
Following the events of the first Professor Layton game, the young heiress Flora Reinhold comes to stay with the Professor. If you haven't played through the first game yet, this is a spoiler for at least one plot element. However, she is clearly present in the second and third games, (occasionally) promotional art, and the prologue to the prequel movie, Eternal Diva.
Q.U.B.E. 2 assumes the player is familiar with the plot of the first game's Director's Cut, meaning the plot misdirection in the latter (I.E. 919's claims that you're actually in an underground government testing facility) can immediately be taken as bullshit by those who've already played the sequel.
Being the final volume of a trilogy, A Crack in Time outright summarizes Tools of Destruction and Quest for Booty in its unskippable intro FMV (as the game needs to install data, so interrupting it would otherwise corrupt).
Red Dead Redemption: Undead Nightmarestarts at a point that was near the very end of the original Red Dead Redemption, so a lot of spoilery stuff is liberally stated. For example, Luisa, Bill, Dutch, and many others are dead, Reyes has taken control over Mexico, and Ross has released John's family from captivity.
The postgame of Undead Nightmare also reveals that John dies. It doesn't reveal how it happened though.
Rune Factory Tides Of Destiny had its manual list Mikoto as an available bachelorette, spoiling the fact that she is a woman. The player might be able to figure this out themselves while playing the game, but Mikoto doesn't officially reveal herself to be a woman until a post-plot point, when she actually gets romanced.
The Sam and Max: Season Two (a.k.a. Beyond Time and Space) Collector's DVD cover◊ spoils what T-H-E-I-R spaceship really looks like. The box art for the Wii port also shows the spaceship too.
In Shadowrun Returns, anyone familiar with the tabletop setting will know that the Universal Brotherhood is a front for the Insect Spirits, but your character won't learn that until near the endgame.
In Shadowverse, Yuwan's story takes place at the same time as "The Morning Star" chapter, which takes place after every other character's story. Naturally, it spoils tons of events that occur. This is especially jarring since the later chapters in each character's stories are meant for veterans with better decks to deal with the illegal decks the AI uses, while Yuwan's story is meant to be a tutorial for Portalcraft like the other characters' early stories.
The premise of Shantae and the Pirate's Curse spoils the ending of Shantae: Risky's Revenge, which had Shantae losing her powers. The trailers are even explicit about it, with the first line being about how "Shantae's magic has been stolen".
In Skullgirls, the existence of The Trinity as real gods instead of just religious figures and also being the creators of the Skullheart is not told in the game until the very end. The Indiegogo campaign to fund new characters, however, had 2 of the 3 members of The Trinity as possibilities with a bio telling who they are.
The back of the instruction manual for the Greatest Hits re-release of Sly 2: Band of Thieves has an ad for the then-upcoming Sly 3 featuring Bentley in his wheelchair and foreshadowing Murray's brief absence from the team.
The European boxart◊ of Solatorobo shows both Red's Hybrid Trance form (though it doesn't identify it as anything) and advertises the fact that you uncover the "mysterious origins" of the world. Both of these do not even show up until the midpoint of the game - before that, Red has no idea he can Trance and the world simply "is".
In Splatoon, the announcement for the 10th North American Splatfest, Past vs. Future, has Callie mention wanting to meet an "odd 'human' thing" from the past. The revelation that the game takes place thousands of years after humanity dies out is only mentioned through the Sunken Scrolls in the single player campaign. This was also the first Splatfest after the Christmas newbie boom. By the sequel, the series' has no problem throwing this factoid around to the point where it's easy to forget that it started as hidden background lore you had to go out of your way to find. It even gets mentioned as part of the Palutena's Guidance on Inkling in Super Smash Bros. Ultimate.
StarCraft suffers quite severely from this, thanks to the fact that the expansion pack "Brood War" centered around the Queen of the Blades, formerly known as Sarah Kerrigan, even going as far to have her get all the attention for the merchandising. In case there was a chance that someone didn't recognize her, Starcraft 2 instead used a flashback of New Gettysburg in their commercials and promo material.
In Starcraft II, the official site description for Heart of the Swarm gives away the ending to Wings of Liberty that Kerrigan gets deinfested.
Sunless Skies will spoil one of Fallen London's deepest secrets right off the bat: the cosmology of its universe and the true nature of the stars as the settings' nigh-omnipotent gods. Them being killed off is the main premise of Sunless Skies.
One of said characters appeared as a playable character in a preview for the upcoming "Second Original Generation".
Super Smash Bros. has pretty much everything in the game, be it trophy descriptions, spirit abilities, Snake codec/Palutena's Guidance conversations, or even a character's moveset as potentially this. Some examples include:
As stated previous Nintendo doesn't seem to consider Sheik's identity in Ocarina of Time as much of a spoiler, what with Zelda's ability to turn into Sheik in Super Smash Bros. Melee. This was mitigated somewhat from the fourth game onwards, when the removal of transformations made them separate fighters on the roster, but the hidden conversation that the Kid Icarus: Uprising cast have about Sheik still has Pit asking if they're actually going to pretend that the character isn't just Zelda dressed as a ninja.
Fans of the EarthBound series that haven't played its sequel, MOTHER 3, may want to avoid Brawl. Brawl includes one of the last areas of the game as a stagenote The stage returns in Ultimate, the next-to-last boss of the game serves as a boss in the Subspace Emissary mode, and Lucas's trophy text mentions how he would eventually have to fight his brother Claus in the end. Possibly in response to this, Lucas's trophy in Wii U/3DS doesn't mention anything about the plot of the game.
The trophies you collect are prone to this as well. Some of them have spoilers for other games in them (in Melee, the trophy description for Custom Robo 2's Annie ends by saying, "At the climax of the story, Nanase fell prey to temptation and stained her hands with the illegal robot Majei. This act ultimately set the stage for her undeniably tragic end").
Palutena's reveal trailer for the fourth game not only states casually that Pit had to fight Palutena before, but that she was controlled by the Chaos Kin at the time. (The game initially leads you to believe she'd done a FaceHeel Turn of her own free will) Both are major spoilers for Kid Icarus: Uprising.
Upon seeing Lucina as a playable character in Wii U/3DS, it doesn't take a lot of brain effort to deduce that she is the Masked stranger that was impersonating Marth in Fire Emblem Awakening, especially since she is wearing the same clothes as Marth (who is also in the game and who she is a Moveset Clone of), and that the hat Kirby gets for copying her is specifically her mask (which also appears within one of her taunts). It also doesn't help that Lucina is the first Fire Emblem character to have both Figma and amiibo available, and the former comes with the Compressed Hair and the Cool Mask.
In the case of Xenoblade, the 3DS version of Wii U/3DS lacks any major spoilers, but the Wii U version features a clearly labeled trophy of Mecha-Fiora as an item in Smash Tour, and the trophies for Xord and Jade Face spoil major plot points regarding Face Mechon. Ultimate' adds Mecha-Fiora to Shulk's Final Smash, and Sakurai even pointed out the change in the E3 2018 Direct.
Wii U/3DS also attempted to undo the massive spoiling of Porky's role in Mother 3 by having his trophy's list of appearances only show EarthBound...even though it reuses his design from Brawl, and explicitly states that he appears in Mother 3 anyway.
Many of the spirits in Ultimate reference certain plot points from their games of origin, such as Paz's spirit battle having the occasional rain of Bob-ombs, and her ability allow the player to spawn with one Bob-omb equipped, both in reference to her death by surgically implanted bomb. But the most blatant examples are the ones that can be enhanced, with a lot of these enhanceable spirits gaining a form that spoils a major plot twist in their original game, such as Rodin transforming into his Bonus Boss form.
Then the trailer for the Hero managed to do this to Ultimate itself, as the very first shot of the trailer briefly shows the secondary antagonist of World of Light, Dharkon. Those who hadn't reached the point in the mode where the character is revealed ended up being treated to the game's Plot Twistjust by showing it onscreen.
The reveal of SHODAN (the primary antagonist of the original game) in System Shock 2 (which occurs roughly halfway through the game) is considered by many to be one of the most shocking and surprising plot twists in any survival horror game in recent memory. It probably would have been a bigger surprise if it wasn't already spoiled by the game's boxart (which has SHODAN front and center) or the game description on the back of the box.
In Tales of Destiny 2, there's no way to play through the game without learning Leon betrayed the party and died in the first game. There's also a whole museum dedicated to the events of the first game, but it's at least an optional area.
Like the example of MOTHER 3 and Super Smash Bros. Brawl, English players who never played Japanese version of Tales of Graces, but will play its expanded version Tales of Graces f in 2012, will no doubt be spoiled by the very cover if one looks close enough that both Asbel's eyes aren't the same color, even though they are throughout the most of the game, and Richard and Sophie wear some new clothes not present in the main arc, implying that Richard and Sophie don't die at the end.
In Tales of Symphonia, the fact that there are actually two worlds is supposed to be a big reveal several hours into the game. Of course, it's impossible to read anything about this game without that fact being spoiled, including the back of the game case, where it says, "The line between good and evil blurs in this epic adventure where the fate of two interlocked worlds hangs in the balance."
Mithos being the Big Bad is frequently mentioned, although it's not always mentioned that he's Mithos the hero.
Tales of Xillia 2 made no effort with both its boxart and trailers to hide the fact that Gaius and Musee, the primary antagonists of the prequel, end up doing a HeelFace Turn after their defeat.
If you got on Team Fortress 2 after Meet the Pyro came out, but hadn't seen it yet and noticed that you had "Pyrovision Goggles" added to your inventory, well... the big surprise of the short was ruined for you.
In the Uncharted series, Sully's continuing presence in the sequels make it clear that he survives his "death" from early on in the first game which was treated as a legitimate twist in Drake's Fortune.
Warframe couldn't even wait longer than the next major update to casually toss around spoilers for major story quest "The Second Dream". The quest revealed that the Tenno are really children who gained powers after an accident in the Void, and they've been remotely piloting Warframes in a kind of lucid dream ever since the Old War. The next major update after its release featured another major story quest, The War Within, that served as a sequel to The Second Dream; take a guess as to what all the promotional material showcased. To make matters worse, the splash screen when loading up the game was changed to show off this spoiler front and center.
The Plains of Eidolon update made it even harder to avoid these spoilers. The main feature of the update was the eponymous open-landscape area, which was placed on Earth to make it accessible to new and veteran players alike. During the day, the Plains offer typical open-world fare with Grineer outposts to raid, fish to catch, and gems and ore to mine; at night, however, Sentients come out to prowl, and the only way to defeat them is to utilize the highly-spoilerriffic mechanic introduced at the end of The War Within, namely the ability to switch to your Operator during combat, a fact the patch notes heavily hint at. Said mechanic has also been tightly integrated into the overhaul of the Focus system, itself now considered an open secret; while the U18 patch notes were hesitant to even mention its name, PoE's patch notes went ahead and spilled the beans on everything, with only a brief warning at the start of the section to inform players of potential spoilers. The update's hype site also joined in on the fun, sandwiching a section on Focus 2.0 right at the page's halfway point.
The Witcher Saga ends with Geralt and Yennefer dying pointlessly and Ciri disappearing into worlds unknown. Anyone who plays the first game, which acts as a sequel to the books, will have this spoiled right from the start.
The trailers of The Witcher 3: Wild Hunt present the titular Hunt as a mysterious and unknown menace, when the readers of the original books, as well as the people who simply paid close attention to the last chapter of the previous game already know that they are a race of imperialistic elves from another world.
In World of Warcraft, players who don't haven't completed Drakuru's quests in Grizzly Hills (and who may not have even met him), will likely have the twist spoiled if they complete Drak'theron Keep with a player who has his last Grizzly Hills quest, which reveals that he's working with the Lich King. Similarly, the Black Knight is listed as the prerequisite for the achievement for completing the Trial of the Champion, spoiling the twist that he comes back from the dead. Icecrown Citadel raids often advertise themselves as being up to Saurfang, which prematurely reveals that Varok Saurfang's son was reanimated as a death knight after the Wrathgate battle.
Due to the nature of questing through Northrend, players are much more likely to run into this in Zul'Drak, the zone after Grizzly Hills, when they begin the Ebon Blade quests and see that Drakuru is a Scourge commander running a necropolis.
The current loading screen for Northrend shows the Lich King is not Arthas. When players defeat the Lich King, Bolvar Fordragon takes Arthas' place, because without a Lich King the Scourge will go out of control.
Due to its lore-heavy nature, World of Warcraft spoils a lot of twists about its predecessor, Warcraft III. Namely, Arthas as the second Lich King, what happened to Illidan, the Blood Elves, and so on. Warcraft III however does not spoil as much about Warcraft II in comparison, what with the two stories focusing on completely different sets of characters each time.
The cover of Yu-Gi-Oh! GX: Spirit Caller, a video game based on the events of the first and part of the second seasons of the show, spoils the fact that Syrus is promoted to Ra Yellow, even though he even starts off in Red in the actual game.