[[quoteright:206:http://static.tvtropes.org/pmwiki/pub/images/RE0_Billy_and_Rebecca_4381.PNG]]
[[caption-width-right:206:[[Creator/SamuelLJackson Enough is enough! I had it with these motherfucking zombies]] [[Film/SnakesOnAPlane on this motherfucking train]]!]]

'''''Resident Evil Zero''''' is the fifth main game in the ''Franchise/ResidentEvil'' franchise, released for the {{Nintendo GameCube}} in 2002. It serves as a prequel to the original ''[[VideoGame/ResidentEvil1 Resident Evil]]''. Initially slated for the {{Nintendo 64}} as a follow-up to its port of ''VideoGame/ResidentEvil2'', the original version of ''Zero'' was scrapped halfway through development when Creator/{{Nintendo}} unveiled their next home console, the [=GameCube=]. Rather than the release the game on a dying platform, Creator/{{Capcom}} decided to bring it to the next generation instead. At the same time, Creator/ShinjiMikami's team began development of a remake of the first ''Resident Evil'' (otherwise known as the ''[=REmake=]'') exclusively for the [=GameCube=]. The development of the two projects overlapped and both games ended up sharing many of the same assets, specifically the same character model for heroine Rebecca Chambers. As a result, ''Zero'' ended up finishing its development only a few months after ''[=REmake=]'' was released. ''Zero'' has remained a Nintendo-exclusive game in the series, with the only other version of the game being the {{Wii}} port released in 2008.

Bravo Team, one half of the Raccoon Police Department's elite [=S.T.A.R.S.=] unit, is heading into the Arklay Mountains to investigate recent "cannibal murders" before a mechanical failure brings their helicopter down. Bravo Team searches the nearby area and discovers a crashed military police van; it contains the van's murdered drivers and a transport log for former Marine Lieutenant Billy Coen, scheduled to be executed for twenty three murders. When Bravo Team [[LetsSplitUpGang separates to search for Billy]], new team member Rebecca Chambers finds her way to a broken-down train -- the Ecliptic Express -- in the middle of a forest.

Rebecca's got incredible luck for her first day on the job: she not only encounters Billy, but also finds herself face-to-decaying-face with scores of zombies, who force Rebecca and Billy to work together in order to survive. After escaping the train, Billy and Rebecca find Umbrella's Management Training Facility at the end of the tracks, where their struggle for survival pits them against hordes of Umbrella's nightmarish bio-weaponry [[spoiler:and the mysterious Dr. James Marcus (who bears his own grudge against Umbrella).]]

''Zero'' employs a character-switching system where the player controls both protagonists, Rebecca and Billy, throughout a single playthrough. The player can have Billy and Rebecca explore the same areas together (with one character controlled by the player and the other by the computer) or split them up. Knowing when to stick together or split-up is integral to solving many of the puzzles. Another big change to the game includes the elimination of item boxes. Instead, Rebecca and Billy can drop their items anywhere and retrieve them from the same locations where they were dropped.

Furthermore, it is thus far the final game in the franchise to use the original pre-set camera backgrounds and exploration-oriented game design before ''VideoGame/ResidentEvil4'' marked the series' [[ActionizedSequel shift towards action and shooting]].
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!!This game includes examples of:
* ActionGirl: Rebecca, sort of. She's certainly much braver and more capable then her [[DistressedDamsel earlier/later self]] from ''Resident Evil''. Easily justified considering that by that ''Resident Evil'', she's been up for several days straight and is running on nothing but fear and adrenaline in the middle of a ZombieApocalypse. However, in ''[[{{VideoGame/ResidentEvilTheUmbrellaChronicles}} The Umbrella Chronicles]]'', we find out she has at the very least had a nap.
* AlwaysClose: No matter how quickly you get to Rebecca, she is always saved just in time when she's dangling from a ledge.
* AndThenJohnWasAZombie: Edward Dewey becomes a zombie shortly after being killed by zombie dogs, while [[spoiler:Dr. Marcus becomes the Leech Queen.]]
* AndYourRewardIsClothes: Rebecca gets her cowgirl ensemble from ''[=REmake=]'', plus a new leather outfit, while Billy gets a fancy suit. Since the closet is located only in the train at the beginning, it becomes impossible to change back outfits after reaching the research facility.
* AwesomeButImpractical: The Hunting Gun. Powerful, but only holds two shells at a time and takes up two precious inventory spaces like most of the other heavy weapons. Most players will likely dump it for good not long after reaching the Training Facility, seeing as the other shotgun can be found relatively quickly which can hold five more shells.
* {{Badass}}: Billy, a former Marine. In ''The Umbrella Chronicles'', he uses his handcuffs as makeshift brass knuckles, and is also capable of dropkicking a full grown man in the face.
* BehindTheBlack: Inverted with the leech zombies purely for shock and surprise. There's a few rooms you'll enter and the layout of the room means the leech zombie ''should'' see you as soon as you're in the room, but it won't start attacking until the camera angle changes to show it, at which point the ScareChord and PsychoStrings start up.
* BigCreepyCrawlies: The bosses include a giant scorpion and a giant centipede. The regular monsters include the smaller-but-still-giant insect-things (the Plague Crawlers) and the Web Spinners (though there are only five of them in the game). And let's not forget all the leeches.
* BodyHorror: [[spoiler:Dr. Marcus]] is probably the best example. There's just something repugnant about a guy vomiting several dozen fist-sized black leeches and copious amounts of slime, after which they crawl all over him and ''fuse'' with him to change him into the Queen Leech.
* ChainedByFashion: Billy only managed to break one arm free when his truck overturned and spends the entire game with his cuffs hanging off of his left wrist.
* ClownCarGrave: Justified in that not all corpses reanimate at the same time and there were dozens of people on the train when it was attacked. You can see corpses still in their seats or lying on the floor all over the train, so it makes sense that the "fresh" zombies are passengers finally completing their reanimation and shambling off to hunt.
* ContinuityNod:
** Rebecca at one point visits the turntable and the entrance to Birkin's lab from ''VideoGame/ResidentEvil2'', which establishes that the cable car ride in ''[=RE2=]'' took a lot longer and covered a lot more ground than anyone thought before this game was released.
*** [[FridgeBrilliance Well, you were busy fighting off Birkin in that ride, so you weren't really paying attention to the distance, were you?]]
** The opening text crawl goes out of its way to not only mention Raccoon City and [[VideoGame/ResidentEvilCodeVeronica Rockfort Island]], but also Sheena Island from ''[[VideoGame/ResidentEvilGunSurvivor Resident Evil: Survivor]]'' as locations of T-Virus outbreaks.
** A subtle one. Rebecca is unable to operate the piano to get the battery, justifying why she had to practice in the first game.
* CreepyCentipedes: Centurion, who's big enough to devour people whole.
* CutscenePowerToTheMax: Billy diving into [[BulletTime bullet time]] while shooting the leeches off Rebecca.
** Rebecca gets her own when she ''ducks'' through an otherwise typical InsurmountableWaistHeightFence.
* DeathFakedForYou: [[spoiler: Rebecca allows Billy to escape at the end by falsely reporting his death.]]
* DemotedToExtra: The zombie dogs make just two appearances during the entire game, and only on the train.
* [[DoorToBefore Door to Before]]: You don't deposit spare items in the item box anymore. You just drop them on the ground and have to backtrack to pick them up. To make this easier, nearly every stage of the game has shortcuts that let you go back to an earlier part of the game. Except the train, obviously, though any items you left on the train end up on the floor in the room where the train crashed.
* EasyModeMockery: Beating the game on Easy will not unlock the special weapons.
* EpisodeZeroTheBeginning
* EverythingsBetterWithMonkeys: Horribly averted with the Eliminators, psychotic albino apes that make very good DemonicSpiders.
* EvilLaugh: [[spoiler:Dr. Marcus]] is quite fond of this.
* FemaleAngelMaleDemon: The statues of good and evil.
* GiantSpaceFleaFromNowhere: Most of the bosses. At least the Stinger was explained away in a file that says the researchers on the train were studying it, prior to the whole "attack of the killer leeches" thing. It was probably being transported on the train and got broken free during the whole mess.
* GrapplingHookPistol: Reasonably subverted. The hookshot is quite large (taking two blocks of inventory space to have, similarly to large guns), it can only hold 80kg without getting damaged, and is slow.
* TheGreatestStoryNeverTold: The only witnesses to the events of ''Resident Evil 0'' besides Rebecca are [[spoiler:the [[DeathFakedForYou officially dead]]]] Billy, Wesker, and, to a lesser extent, Birkin, who was watching the training facility's security feed for at least part of the game. There's no indication that Rebecca told Chris Redfield or Jill Valentine what happened.
* HandCannon: The magnums, as usual.
* {{Handguns}}: As usual, the staple weapon, though the ones Billy and Rebecca start out with are subtly different. Billy's is slightly more powerful and will randomly headshot zombies, and either gun can be upgraded later on for more power and faster firing.
* HiddenDepths: Gruff, short-spoken Billy [[spoiler:is remarkably talented at playing the piano.]]
* HugeGuyTinyGirl: One way of emphasizing Billy and Rebecca's "unlikely partner" status.
* ICantUseTheseThingsTogether: Some items have very specific uses. For example, early on there's a room you can get trapped in because there's something stuck in the keyhole, and the character mentions they need something sharp to poke it out. The knife doesn't work, and if it's Rebecca, neither does her mixing kit which is shown to include syringe needles. The only way to open the door is to find an ice pick and give it to the character.
* IGaveMyWord: Invoked by Billy when saving Rebecca.
* InsurmountableWaistHeightFence: Billy, a former Marine who just survived going through a water treatment facility's river with a zombie shark, cannot swim across a three meter gap of water to get a valve handle.
* InventoryManagementPuzzle: Pretty much the whole game. Each character can only hold six slots worth of items, and the series-standard item boxes are nowhere to be found. If you don't know what's coming, you'll probably have to trek back and forth to whatever room you've designated your item room to resupply.
* InvisibleBackupBand: [[spoiler:Dr. Marcus]] inexplicably has instruments playing in the background when he's singing during the opening scene. Later on, he sings with no backup whatsoever.
* IWontSayImGuilty: Billy refuses to confirm or deny whether or not he really did commit the murders he was sentenced for. [[spoiler:He didn't. The flashback reveal that it was his commanding officer who was responsible. When Billy tried to stop it, he was knocked out cold. When the massacre was discovered, the unit pinned the blame on him.]]
* KillItWithFire: Flame grenades and molotov cocktails are the best weapons to use against leech zombies; not only do they inflict the most damage, they cause them to die ''without'' exploding.
* KnightInSourArmor: Billy.
* LetsSplitUpGang: Can be done by the player as part of the partner system. Some puzzles also force you to this.
* LoadsAndLoadsOfLoading: Permissible on the [=GameCube=] version, because of the time of release and the high end graphics. On the Wii, however, this becomes frustrating very quickly.
** Though if you split your characters and move them to separate rooms, you can toggle back and forth between them without any of the loading time it takes to move from one room to another with ''both'' characters.
* MadeOfIron: Billy, when compared to Rebecca.
* {{Minigame}}: Leech Hunter.
* NeverSplitTheParty: For the most part, the game's easier if you keep Billy and Rebecca together, since it lets you put out twice as much firepower quickly. However, there's parts where you have to split them up, and others where it's easier to sneak by monsters if there's only one of you around. Particularly anything with leech zombies.
* NinjaPirateZombieRobot: Eliminators, which are ''zombie monkeys''.
* OddCouple: An innocent, delicate-looking, 18-year-old rookie of an elite police force teams up with the escaped convict she is supposed to be arresting, a gruff, cynical, rather intimidating-looking ex-Marine who was sentenced to death for murdering 23 people. Their relationship starts as TeethClenchedTeamwork, but they eventually become FireForgedFriends after he saves her life repeatedly, proves to be a decent guy, and she [[spoiler:lies to her team to protect him.]]
* PapaWolf: See OddCouple above; Billy becomes a "big brother" version of this to Rebecca over the course of the game.
* {{Prequel}}
* PsychoStrings: The leech zombie theme.
* PuzzleReset: Thankfully, all the puzzles in the game. The most notable is the one near the end of the game. It requires you to push wooden crates to one side of a pit and fill it with water. Two catches: One, there's a metal one in there too that needs to be dealt with. Two, there's also a grate that impedes how you move the crates.
* RefrigeratorAmbush: A zombie pops out of the refrigerator in the dining car after you've solved a few puzzles.
* RoaringRampageOfRevenge: The "mysterious youth"/[[spoiler: Dr. Marcus]], as he is sure to announce in every single line of dialogue. His rampage sets in motions the events of the rest of the series.
* ScareChord / PsychoStrings: Whenever a leech zombie shows up.
* ScaryScorpions: The first boss, the Stinger, is a scorpion the size of a pickup truck.
* SelectiveMemory:
** Inverted. At one point, the player has [[LetsSplitUpGang to split Rebecca and Billy up.]] The one who goes upstairs (by using the hookshot) will find a file that hints at the combination to a locked room. It is explained how the other character gets the dial (which is inexplicably off) to enter the combination, ''but not how they know about the file, let alone the password''. And that knowledge is needed for the other character to progress.
** Just before Billy has to save Rebecca from falling into a chasm. In order to unlock the door, Rebecca needs to pick up a note that says what the power settings need to be. But, when she falls into the chasm, Billy needs that note, because it hints that [[spoiler: he's got to go through the boiler room.]] So he really shouldn't know that. Both of these instances, though, are because the characters are both controlled by one person.
* SemperFi: Billy, badass former Marine.
* ShotgunsAreJustBetter: You get two in this game: a Hunting Gun, an over-under shotgun that only holds two shells but is slightly more powerful (and actually fired correctly, from the shoulder), and the usual pump-action shotgun, which holds more shells but is slightly less powerful.
* ShoutOut: [[ShoutOut/ResidentEvil0 Shout Out Page.]]
* SolveTheSoupCans: The train's E-brake system. There's [[VoodooShark no possible rationale]] for the puzzle that doesn't make it even crazier.
* StockVideoGamePuzzle
* SuspiciousVideogameGenerosity: Right before the final boss, you find some ammo and healing items.
* TakeYourTime:
** The player can take as long as they like on the speeding train until the sudden urgent need to slam on the brakes appears.
** Getting to Billy, after he's nearly drowned is also a moment to take your time.
** Averted at one point when Billy must save Rebecca from falling into a chasm. If he dawdles for too long, Rebecca dies. This requires a good portion of time and not realizing [[spoiler:that you need to go through the boiler room.]]
* TheMedic: Rebecca, as the field medic of S.T.A.R.S.
* TheWormThatWalks: The leech zombies and [[spoiler:James Marcus himself.]]
* ThoseTwoBadGuys: [[MagnificentBastard Wesker]] and [[MadScientist Birkin]], who show up at several points in cutscenes watching the events on the security cameras and attempting to contain the situation.
* TimedMission:
** Stopping the train before it crashes.
** Saving Rebecca from Centurion.
** Saving Rebecca before she falls, although most players won't realize it unless they wait around long enough.
** The final boss fight.
* TwoKeyedLock: More than a few of these around to take advantage of the partner system.
* WhatHappenedToTheMouse: Billy hasn't been heard from in the series since, and neither has Rebecca after the events of the original game. Canonically, Rebecca is supposed to have survived the events of the original game.
* WickedCultured: [[spoiler:Dr. Marcus. [[HumanoidAbomination humanoid abomination]], talented opera singer?]]
* ZombieApocalypse
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