Typically, games let you make choices. Some games let you make choices that have significant effects on the game world. The Big First Choice is an early player choice — sometimes occurring before proper gameplay even starts — that has a massive effect on the game.
You escape the enemy's dreadnought aboard your commandeered shuttle, with the rescued rebel leader in tow and mere seconds to spare before the explosive charges you planted crack the monstrous ship in half. Not a bad job for the tutorial level. As the adrenaline wears off, the rebel leader congratulates you for your courage and offers you a chance to work alongside her to help free the galaxy from the Dark Order's clutches. But your hero would have to give up his grand life as a space mercenary, an outlaw-for-hire: certainly he's no friend of the Order, and he's more than happy to fight them on his own time, but he chafes at taking orders from anyone.
You ponder the decision for a few seconds, then have your hero turn down the offer with characteristic nonchalance. You then spend the next twenty hours of this epic space opera being inadvertently dragged into one conflict after another, meeting the rebels under awkward circumstances, and generally making life hell for the Order. Finally, when all's said and done, you get to put a bullet between the eyes of the Shadow Prince, collect your reward and fly off into the sunset.
Feeling good about your victory, you go online to discuss the game. But what's this? You don't remember an infiltration mission aboard a satellite. And a romantic subplot with the rebel leader? How come no one's talking about the MX-6000 railgun that got you through the final stages, but they're all gushing over that multi-missile launcher that the Elite Mooks had towards the end? Certainly you don't remember getting one.
After skimming a few threads, you can't help but wonder: did you even play the same game as everyone else?
The answer: not quite. As it turned out, a lot more was riding on the rebel leader's innocuous first question than you ever could have guessed. By making one choice or the other, you determined the entire course of the rest of the game.
Not every game is quite as extreme as this example, but the Big First Choice (or second, or third) is a common way of extending the life of a game by making the player's choices at key points have a dramatic effect on the way the game plays out - perhaps even the way the game plays, period. Multiple playthroughs are absolutely necessary to wring 100% Completion out of games that feature such choices: sometimes the different paths will converge again at the end, but it's just as likely that each individual choice will lead to a different ending.
One method of Story Branching. Subtrope of For Want of a Nail. Compare Multiple Game Openings, where the the story branches even before you make the first in-game choice, and Last-Second Ending Choice, where you play through most of the game before a major and irrevocable plot split. Contrast But Thou Must!, which might look like a big choice, but really isn't.
- At about the end of the first third of Indiana Jones and the Fate of Atlantis, the game splits into one of three possible paths depending the player's choice: the combat-centric "action" path, the self-explanatory "puzzle" path, or the "team" path where Indy travels together with Sophia. These paths all converge at the last act in Atlantis, and beating all of them is required for the maximum Indy Quotient points.
- In the Adventure scenario of Clonk's "Metal and Magic" pack, you can either choose becoming a mage or a paladin, and both choices lead to quite a long story...or you can become a roadsweeper, which ends the story in about five minutes.
- In Dreamfall Chapters Zoë's first choice is when she wakes up from the coma, does she start working in her chosen profession as a bioengineer, or does she try something different. While the story will play out the same, some of the important characters will be different.
- Kingdom Hearts I and its sequel ask the player to choose which skills to emphasize and de-emphasize (strength, magic or defense) and how quickly they level up at the start of the game. Woe to the player who might unknowingly choose to level up slowly at the start.
- In Final Fantasy X-2, at the beginning of Chapter 2, you have to decide which of two factions to give an important MacGuffin to. This affects which faction-related sidequests will be available to you later.
- In the Pokémon series, your choice of starter Pokémon determines your rival's starter as well: if you choose the Grass-Type starter, he'll choose the Fire-Type; the Fire-Type starter, the Water-Type; and the Water-Type starter, the Grass-Type (i.e. whichever you choose, he gets the one that's strong against it). Yellow is an exception: there, your starter is always the Electric-Type Pikachu, and your rival's Eevee will evolve into Vaporeon (weak against Electric), Flareon (neutral against Electric), or Jolteon (strong against Electric) depending on how often you lose to him. Your rival's starter (or his starter's final form) will also determine his final team. Some of the later games have another rival character who gets the remaining starter Pokémon (the one that is weaker to yours).
- Also, in the FireRed and LeafGreen remakes, your choice of starter determines which of the Legendary Beasts from Generation 2 will roam the Kanto region: choosing Charmander will cause Suicune to appear, choosing Bulbasaur will cause Entei to appear, and choosing Squirtle will cause Raikou to appear.
- In Pokémon Black and White, your choice of starter Pokemon determines both which gym leader you fight in the first gym (as with your rival, it will always be the one with a type advantage), and also which one of three Pokemon you receive as a gift prior to the battle (which will always have a type advantage over the gym leader).
- Subverted in Radiant Historia, one of your earliest decisions is whether to stay with Heiss in Special Intelligence, or join your friend Rosch in his new brigade. However, due to the nature of the game, the paths are not truly mutually exclusive, and because of some interplay between the two diverging timelines, it is not only possible but necessary to experience both, making only the order you do events impacted by your choice.
- Front Mission 3 has quite possibly the most extreme example in all of gaming: an innocuous choice at the beginning (whether or not you want to hang out with an NPC for drinks) determines your entire path through the game. There are two complete storylines with wildly different results throughout, all hinging on that little choice. If you choose not to go with your friend, you have time to read your email and learn that your sister is working at a military base in town. Later, when an explosion occurs while you are at the base, you try to find your sister. But if you do go with your friend, you don't check your email before going to the base, so you leave after the explosion and don't learn until later that your sister was there, causing you to try to sneak in to find her. In both stories you get help from opposing factions which leads to the very different plots, and characters who are allies in one route are enemies or throwaway NPCs in the other one. It's very nearly two games in one.
- Very early on in Soul Hackers, the Player Character is asked what his very jittery companion Hitomi is normally like. The answer given changes one line of her dialog... and Nemissa's entire skill tree. All the possibilities are about equal in the end, but you're given no indication these two things are related until you answer different next time and wonder why on earth one of your party members is learning wildly different skills.
- Exaggerated Trope in Super Paper Mario. Your first choice of the game is whether you will accept the challenge of saving the world. If you say no three times, you don't save the world and automatically get a Game Over.
- Early on in Wolfenstein: The New Order, the player is given a choice of saving one of two characters, Fergus or Wyatt, which significantly impacts the storyline and several mini-games for the rest of the game.
- Battle Realms, at the beginning of Kenji's journey, he must choose whether to slaughter or save peasants. If he saves the peasants the takes the Dragon path, if he kills them he takes the Serpent path.
- Fire Emblem Fates builds its entire premise on this. The protagonist is a Child of Two Worlds, born into the royal family of Hoshido but raised by the royal family of Nohr. The two kingdoms are at war, and shortly into the game the protagonist has to choose a side to support. Which side they choose affects the story so drastically it branches into two separate games! And there's a downloadable third route where they side with neither, which branches into a third storyline. Each has a completley different set of chapters and recruitable characters.
- Fire Emblem: Three Houses early on has the protagonist choose which of the Three Houses of the Officer's Academy will under their guidance, with each House consisting of students from a specific nation. While the mission and battles are the same for all Houses during the first Story Arc, it diverges after the five-year Time Skip where the continent is engulfed in war, and the protagonist sides with the nation whose students they taught with the exception of the Black Eagles (where you have an extra choice if an optional story event is seen to do a FaceHeel Turn alongside Edelgard).
- Tactics Ogre features a major divergence at the end of its first chapter, placing the player on one of two mutually exclusive paths (until the PSP Updated Re-release and its New Game+). There is a secondary split in one of the paths, and all three routes eventually converge, but the characters and resources available will be vastly different by the end.
- Tactics Ogre: The Knight of Lodis is nasty about this one. Not only does the big choice determine Alphonse's loyalties and the path the story takes, but it looks completely innocuous. It's about the third choice you make (with the previous two being yes or no to recruiting a character), it's simply whether Alphonse quietly accepts Cybil's plan or voices his opinion, while ostensibly going along either way. Unless you play the game again or look at a guide, you could reasonably have no idea the decision did anything at all.
- Front Mission 3 has a choice right after the tutorial about whether to accompany a friend or not. It's minor enough many players don't even realise it's significant, but it sends the game down one of two completely different storylines, essentially putting the player on opposite sides of the war and with a different third major character in your party.
- The very first thing the player must do in Spore is decide whether his character should be a herbivore or carnivore. It is possible to reverse this choice during the cell stage by swapping mouths, but once the cell stage is over you're stuck with it. The choice of herbivore, carnivore, or omnivore determines which mouths you can use in creature stage.
- At the start of Metal Gear Solid 3: Snake Eater, the player will be asked to choose their favorite game in the series. Picking Metal Gear Solid makes Snake's stamina decrease more slowly; picking Metal Gear Solid 2: Sons of Liberty starts the player wearing the Raikov mask in the very first cutscene; and picking Metal Gear Solid 3: Snake Eater (in the Subsistence remake) unlocks a "Peep Theatre" cutscene. This choice has no impact on the story, however.
- In The Nameless Mod, after leaving the starting area, the player has the option to join either PDX or World Corp. It affects the entire plot of the game, most of the missions, and even which locations you encounter.
- In the first chapter of Eternal Darkness, you have to pick up one of three artifacts. Which one you take determines which of the three Ancients will be the Big Bad of your playthrough, which also affects which of three attributes (Health, Magick, and Sanity) the protagonists are particularly strong/weak in and by extension, the special properties of Elite Mooks in that playthrough. Going through all three Ancients' campaigns via New Game+ is the way to unlock the secret Golden Ending where it's revealed that Mantorok split the timeline in three to kill off all three Ancients in separate timelines before combining them to create a new timeline where all of them are dead.
- A decision made early in Saw II: Flesh & Blood determines who survives at the end of the game.
- In Tsukihime, a few less than obvious choices during the first two days of the story determine which one of five branches it will follow for the rest of it. It doesn't help that some options and branches only become available after you clear other endings.
- In Fate/stay night, you are given a few choices regarding how you follow your day as an Ordinary High-School Student... and the answers you give determine which route you follow for the rest of the game. However, like the aforementioned Tsukihime, the key choice for the 2nd and 3rd routes don't appear until you've already cleared the previous one, forcing you to play through the game (for the first time at least) in the order 'Fate', 'Unlimited Blade Works' and 'Heaven's Feel'.
- In Reflections on the River, the first choice players make is whether to abduct Prince Shun or Princess Yanyu. This sets the game down completely different paths. (However, the result of the choice itself is flipped by the non-chosen character saying Take Me Instead, so you end up going down the path of whichever you didn't select).
- In Mystic Messenger, your very first choice of the game is whether to play Casual Story or Deep Story mode (although the latter becomes available only after you unlock it with 80 hourglasses). The modes diverge greatly after the first day with different love interests accessible on each one (Zen, Yoosung, and Jaehee in Casual Story; Jumin and 707 in Deep Story).
- Before a new game of Monster Prom, the player will be asked a series of personality questions which will determine their starting stats. All perfectly normal and not this trope. They will then be asked a final question which will determine whose route they start on - this decides which events they will get from the beginning, and while it's possible to get another character's ending after this, it's definitely harder, and it'll be almost impossible to get a secret ending.
- Dragon Age: Origins has its eponymous Origin stories: class/race-specific pseudo-tutorial missions, the consequences of which come up again and again throughout the rest of the story.
- In Dragon Age II, your choice of class (mage or non-mage) determines who of the younger Hawke twins dies in the prologue, before their character arc can even begin to unfold. The death of their sibling haunts Hawke for the rest of the game.
- In Dragon Age: Inquisition, pretty much the first major plot choice is whether to approach the mages or the Templars for help with closing the Breach. Doing so effectively allies the Inquisition with the respective faction in their on-going war, causing their enemies to turn to the Elder One instead and be transformed into his brainwashed and disposable mooks for the rest of the game.
- In Sid Meier's Pirates!, your choice of nationality and era determines your starting ship, crew, and home port. The era chosen also determines the balance of power among the four nations on the game map. You are also given a choice of one of four different skills, each of which make a different aspect of the game easier to manage.
- In Alter A.I.L.A., the choice at the end of the prologue determines which faction you (and by extension Green) will side with for the first chapter, and determines who your allies will be.
- Fallout 3 gives you the option of nuking the town of Megaton fairly early on. If you go through with it, you kill off many characters and lock yourself out of any quests there that you haven't completed yet, which can be quite extensive. If you refuse, you miss out on a free penthouse apartment, which is snazzy-looking but not particularly gameplay-relevant (especially since you can get a functionally equivalent pad in Megaton instead).
- The first thing you do in Nox is pick your Character Class, which also decides which one of three largely different storylines the game will follow.
- Early in Wasteland 2, you receive simultaneous distress calls from Highpool and the Ag Center and can only answer one in time to save the respective settlement. The other will be destroyed, and you will be reminded of your choice at every opportunity throughout the rest of the game.
- The Witcher 2 presents the option to ally with the army or the elves, which results in a major divergence of the storyline. There are a few other big choices along the way, as well. The achievement granted for finishing your first playthrough of the game? "Once Ain't Enough"
- Spoofed in Saints Row IV, where immediately after the tutorial you're thrust into the role of President. During your walk to a press conference, your Veep gives you the option between pushing a bill for curing cancer or one for ending world hunger, a confrontation with a cranky Congressman lets you choose whether to "punch a dick in the head" or "punch a dickhead," and finally an annoying actor asks if you want to hang out and watch Nyteblade later. Absolutely none of this matters because in the very next cutscene, aliens attack Earth and abduct you, putting you into the computer simulation you'll spend the rest of the game trying to escape from.
- In the Web Serial Novel Dream High School readers get to make some big decisions off the bat, but one of the first ones that has evident repercussions throughout the rest of the story is joking to somebody who hardly knows you that your name is Grok, Destroyer of Worlds. They believe you, and it becomes your well-known nickname.
- In The Game of Life you can either go to college or enter the workforce straight out. This affects two things right away (how much money you start with and which career paths you can accept) and will impact your overall earning potential for the remainder of the game (which ultimately influences your retirement options).
- In the Gamebook comic book Meanwhile, the first choice you make is to buy chocolate or vanilla ice cream. If you choose chocolate, you are plunged into a series of Mind Screw time-traveling adventures. If you choose vanilla, you eat your ice cream, go home, and the story ends there.
- An early choice in Kim Newman's adult Gamebook novel Life's Lottery is whether your favourite character in The Man from U.N.C.L.E. is Napoleon Solo or Ilya Kuryakin. The answer decides whether you end up joining the social in-crowd at your primary school or becoming a misfit, which branches the novel into two completely different decision trees.
- Happens in a couple of Fighting Fantasy gamebooks.
- In Scorpion Swamp you have to make an early choice about who hires you - working for a good, neutral, or evil character. This affects what your goal is within the swamp and what spell gems (one-off spells) you can take into the swamp
- In Appointment with F.E.A.R. you have to choose what powers your superhero character has before you start the book. This affects the options you have throughout the book.
- In the Literature/Sorcery series, you have to choose whether you are a warrior or a wizard before you start play. This affects your stats and your options (wizards are weaker, but frequently have extra options in the form of casting spells).