Assassin's Creed: It's all a simulation imposed on a man in the near future. It's the very first thing we actually find out in game but when it first came out, all the promo material tried to hide it, and several fans complained that sites were giving away the "twist" in their reviews, though some reviewers tried to hide it.
Assassin's Creed II: This game reveals that the human race was originally created as worker drones by a superior race, who later died off in a catastrophic event. This immediately became the base premise of the overarching Assassin's Creed storyline, to the point where it's difficult to explain the modern-day story without covering this basic information.
Assassin's Creed: Brotherhood: the safehouse where Desmond was transported to for most of the second game is not only in Italy, but a few hours' drive from the Monteriggioni villa.
Assassin's Creed III has you start off playing as British noble Haytham Kenway, despite all the hype for the game being about playing as a Native American Assassin. After a few missions with him, it's revealed Haytham defected to the side of the villainous Templars and the group he spent so much trouble putting together were all Templars. Once you start playing as Native American Connor, Haytham is set up to be the Big Bad.
Danganronpa Another Episode: Ultra Despair Girls: Yuta Asahina is introduced in the first chapter and the fact that he quickly bonds with Komaru and is the brother of one of the survivors from the first game would lead one to think he’d be a major character. Only a few minutes after his introduction, he tries to swim away from Towa City, leading to the reveal that the bracelets on those targeted by the Warriors of Hope have bombs in them that will explode if they get too far away from the city.
Devil May Cry: Near the end of the prologue, Trish removes her sunglasses and looks back at Dante. The camera then quickly focuses on Eva's portrait, revealing that this mysterious woman looks just like Dante's mother.
Nero's right arm is slinged in the prologue cutscene, implying that he's handicapped. Mid-way through the first mission, Nero uses said arm to block Dante's sword, revealing his arm to be of demonic nature which grants him Super-Strength.
The plot starts with Dante, the protagonist of every other game in the franchise, killing Sanctus, the leader of the Order of the Sword, after which demons begin plaguing the streets of Fortuna and Hell Gates start popping up across the island. Nero is left to investigate where the demons are coming from and what part Dante plays in the whole mess.
Devil May Cry 5 possibly tops the above twists by having Dante lose in the Prologue, after which all Hell breaks lose.
The prologue for Digimon Story: Cyber Sleuth ends with The Hero getting attacked by an Eater while trying to log out of EDEN, causing their consciousness to manifest in the real world in a part-digital, part-physical body. A surprising turn of events to be sure, but their nature as an Energy Being and the abilities it grants them are integral to the game's story and form the basis for at least one major game mechanic, so it's difficult to discuss the game without addressing it in some way.
In Eternal Darkness, you play as one character while exploring the Hub Level, but every time you find a page of the titular Tome of Eldritch Lore, you get a flashback sequence where you play as a past member of The Chosen Many. Except the first of these you play as, a Roman Centurion named Pious Augustus, does a Face–Heel Turn at the end of his chapter, transforms into a liche, and becomes The Heavy the rest of the cast ends up opposing in their chapters.
Fate/EXTRA: The game starts off in an ordinary school setting filled with recognizable characters from Fate/stay night and presents itself as a pretty standard Visual Novel in the same vein. After about 20 minutes of play, you discover that the school environment was a digital simulation, all those recognizable characters are NPCs to add to illusion, and you have entered into a massive tournament within the computer for the sake of an all-powerful wish. Then the RPG mechanics show up.
More of a Second-Episode Spoiler, but in Freedom Planet, Torque reveals the "shellduck" look was just a disguise and that he's actually a Space Police officer sent to Planet Avalice to capture Lord Brevon. This happens right after the 2nd stage (out of 12). Furthermore, the promotional media (official posters, trailer and website's character page) doesn't even try to hide the "spoiler", outright depicting him in his true alien form, with no "shellduck" disguise on.
Grand Theft Auto V drops several major drama bombs in the tutorial mission, an Action Prologue detailing the nature of Michael and Trevor's friendship (and even revealing that "Michael De Santa" is a Witness Protection cover for Michael Townley, who wanted out of the game and betrayed his best friend to the FIB), all of which had been kept under wraps before release. It also happens to be the only mission in the game where you can't skip any Cutscenes, so good luck trying to replay the game for a friend without giving away some major spoilers. Given how critical this is to the story, it becomes impossible to talk about single-player without spoiling at least some of it.
Kingdom Hearts II starts with the player controlling Roxas, an all-new character living in Twilight Town (which wasn't explored in depth in its first appearance). Then, it's revealed that Roxas is actually living in a simulation with fake friends and memories, and that he's actually the Nobody of Sora, the first game's protagonist, and he must disappear so Sora can be awakened. The rest of the game is played from Sora's perspective, so it's hard to not spoil that something will happen to Roxas.
The prologue of The Last of Us reveals that Joel had a daughter that was killed by a soldier just hours after the outbreak of the Cordyceps strain.
Commander Shepard's resurrection at the beginning of Mass Effect 2 would be a surprising and dramatic opening, except that it's practically impossible to discuss the game in any sort of depth without that coming up. This doubles-up with Trailers Always Spoil: the announcement trailer had a long list of Shepard's personnel file, ending with: "Killed in action", with a pull-back reveal that Shepard's N7 armor you were seeing had, in fact, just been a piece of chestplate that was grafted onto a Geth unit. Fandom speculation abounded about whether Shepard was faking dead, had somehow been turned into a Geth, or if they HAD died and you were now playing a new character.
Master Detective Archives: Rain Code: Trailers and marketing heavily focused on the The Hero Yuma's fellow Master Detectives from the World Detective Organization. In the game proper, all of them are murdered early into the first chapter, and Yuma's actual allies are a different group of detectives.
It's practically impossible to talk about Metal Gear Solid 2: Sons of Liberty in-depth without mentioning the early-game character switch. Unlike the Assassin's Creed example above, however, most reviewers tried their best to write around the twist until it became It Was His Sled territory. Konami themselves also tried their best to hide the twist in each subsequent Updated Re-release, finally relenting in the HD Collection version which included a brief blurb about the Plant Chapter in its official summary.
After the tutorial of OMORI wraps up, the player is introduced to Omori's real-life self Sunny, revealing that Omori is not real, and that the actual plot of the game is Sunny attempting to reconnect with his friends and come to terms with his greatest failure.
Outer Wilds looks like a cozy space exploration game, where you play as a funky alien cruising your solar system in a mostly-wooden spaceship. Then, 22 minutes after liftoff, your sun goes nova. Then you wake up next to the campfire you started at before the tutorial, but already knowing the launch codes you learned at the end of it. Suddenly the game is a cosmic mystery, as you try to work out why you're stuck in a "Groundhog Day" Loop and how you might escape it, using knowledge you discover from exploring different sites each loop.
Pokémon Legends: Arceus takes place during the distant past of the Pokémon universe, with all of the promotional material revolving around you as a person living in ancient Sinnoh, serving as a talented new member of a surveying group trying to learn more about the area's Pokémon. What all the marketing hid was the actual plot of the title, which reveals almost immediately that it's actually a Time Travel story wherein the player character actually hails from the present-day and is tasked by Arceus to assist in the development of Hisui into the modern region of Sinnoh, while investigating mysterious space-time rifts that are causing chaos in Hisui.
In Return Of The Obra Dinn, you play as an insurance investigator who is sent to investigate an abandoned ship that has reappeared in 1807 after being lost at sea. Other than the gameplay mechanic of using a magic pocketwatch to see people's deaths, the story initially seems to be a realistic age-of-sail mystery, and the player is led to believe everyone was killed by mundane causes such as mutiny. Then the fifth death scene, barely half an hour into the game, gives the Wham Shot reveal that the ship was attacked by a kraken, and it becomes clear what kind of world the game takes place in.
Shin Megami Tensei IV appears to take place in the 15th century in the Eastern Kingdom of Mikado, a middle-ages civilization where demons roam underground and warriors known as "Samurai" are tasked with slaying them. However after passing through a gate deep underground that has gone unopened for a thousand or so years, the heroes discover what the Monastary has been calling "The Land of the Unclean Ones"...which is in fact a modern-day Tokyo that has been living in the aftermath of a demon apocalypse. While the player does have unusual dreams about Tokyo at the start of the game, at the time the exact context of why Tokyo appears in a game supposed to be set in the 1400s wasn't made clear.
Spec Ops: The Line was marketed as a straightforward modern military shooter in the vein of Battlefield or Modern Warfare, but it rapidly became common knowledge that it is in fact a Genre Deconstruction. Exactly what point in the game this becomes clear is subject to debate, but the first instance the player has to fight against American troops (about forty-five minutes into the game) is a fairly good indicator that it's not a straightforward shooter.
Andrew Plotkin's Spider and Web: The entire game is premised on the fact that you are not just a tourist, despite the opening's attempt to mislead you otherwise.
The main Hero Mode campaign has the same start as prior entries: someone stole the city's Great Zapfish and the New Squidbeak Splatoon recruits a teenager off the street to help get it back. Given who the culprits were in the previous two games, a now-retired Cap'n Cuttlefish is not unjustified in accusing the Octarian Army of committing the deed. Except their leader DJ Octavio appears as the first boss, blaming Cuttlefish for his missing troops. Given the aftermath of Splatoon 2, this isn't unjustified either, but the fact that he isn't reprising his role as the Final Boss should be setting off alarm bells for series veterans. Sure enough, after the two men express confusion about what's going on, the ground gives way and New Agent 3 is dropped into the underground world of Alterna, where the campaign truly begins.
The Side Order DLC saw its trailers lack the presence of Marina, a character who was already confirmed to appear in the new story campaign in the initial announcement and promotional art. This was done both to maintain the campaign's fake-out opening where it's implied that she's the final boss — Eight and Pearl defeat and rescue her in the tutorial run — and to hide the subsequent reveal that the setting isn't actually Inkopolis Square, but a virtual reality game created by Marina that has been co-opted by a rogue AI for its own ends.
Tales of Symphonia does this backwards by cutting off as Lloyd is about to name the World Tree. Symphonia is a prequel to Tales of Phantasia, in which the World Tree Yggdrasil was just one mundane example of many gratuitous references to Norse mythology.
One of the main goals of The Legend of Zelda: Tears of the Kingdom is to find Zelda. You very quickly learn that she was actually sent back into the past, to the time of Hyrule's founding.
Undertale's first area, the ruins, will throw some curveballs at you if you take things at face value.
Flowey's the first character you encounter, and is described as "your best friend" in the demo manual. He also reveals himself to be a villain soon after tricking you into following a fake tutorial wherein he's actually trying to kill you.
Following the encounter with Flowey, you are introduced to a friendly monster named Toriel, who makes herself your adoptive mother. Shortly after, you are forced to fight her to progress, which would already be a dramatic twist, but on top of that, the battle will probably end with you killing her, whether you meant to or not, unless you know what to do, which the game will call you out on. The game will also call you out if you killed even one of the random encounters, establishing that Undertale doesn't treat death (even of minor enemies) the same way that other RPGs do. This is a major part of Undertale's premise, but it's bound to be unexpected if you somehow played it without any prior knowledge.
World's End Club starts off with a Danganronpa-esque scenario where a group of kids find themselves trapped in a surreal location with no memory of how they got there, and a Mascot Villain tells them to play a Deadly Game where they must outwit everyone else so that one of them can escape to the real world while the rest perish. At the end of the first level, it seems like the Deadly Game will continue, but it ends up abruptly coming to an end and everyone escapes alive. The real story is their journey back home halfway across Japan and uncovering the mystery of what happened to the outside world while they were gone.
In Xenoblade Chronicles 1, Fiora, one of your party members and Shulk's Love Interest, dies trying to fend off the Mechon attack on Colony 9 at the start of the game. While players going in blind might be shocked by this, anyone who's seen or heard of anything from later in the game will probably be expecting it, both because Shulk's main motivation for the first half of the story is avenging her death, and because it's hard to look at any later scenes involving the party and not notice Fiora's conspicuous absence. In fact, the real twist is that she didn't actually die, but was turned into a Mechon and later rejoins the party.
In Xenoblade Chronicles 2, Azurda performs a Heroic Sacrifice at the end of the first chapter and then regenerates into a smaller, younger form. Thus, it can be rather difficult to explain why everyone refers to that wise, soft-voiced pixie as "Gramps."
Yomawari: Night Alone begins the main character, a little girl, walking her dog, with the game providing a tutorial for the controls. One of these tutorials ends with the dog getting rammed by an oncoming truck. Luckily, most trailers and promotional material keep this a secret, saying that the dog simply went missing. It helps that the little girl believes he's missing, spending much of the game in complete denial over his death.
Yomawari: Midnight Shadows begins with one of the main characters, Yui, burying one of her dead dogs and taking her living dog out for a walk as part of the tutorial. The tutorial ends with her commiting suicide, spending the rest of the game as a spirit that Haru, her best friend, is trying to reunite with. Like the first game, the trailers and promotional material kept the spoiler a secret by saying the two got separated during a festival.
