Resident Evil Zero, the fifth main game in the Resident Evil franchise, came out for the Nintendo GameCube in 2002. It serves as a prequel to the original Resident Evil. Capcom initially slated this game for the Nintendo 64 as a follow-up to that system's port of Resident Evil 2, but scrapped the original version of Zero halfway through development when Nintendo unveiled their next console (the GameCube). Capcom made the decision to move Zero from a dying platform to the next generation instead; at the same time, Shinji Mikami's team began development of a remake of the first Resident Evil (better known as the REmake) for the GameCube. The development of the two projects overlapped, which led to both games sharing many of the same assets (chiefly the character model for Rebecca Chambers). As a result, development on Zero finished only a few months after the release of the REmake. Zero has remained a Nintendo-exclusive game in the series — its lone port remains the Wii port released in 2008.Bravo Team (one half of the Raccoon Police Department's elite S.T.A.R.S. unit) heads into the Arklay Mountains to investigate recent "cannibal murders", but a mechanical failure brings their helicopter down. The 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, a convict scheduled for execution after committing twenty-three murders. After Bravo Team 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 has incredible luck for her first day on the job: she not only encounters Billy, but also ends up face-to-decaying-face with scores of zombies, who force Rebecca and Billy to work together in order to survive. The duo escapes the train, then head down the tracks — where they discover Umbrella's Management Training Facility. Their struggle for survival pits them against hordes of Umbrella's nightmarish bio-weaponry and the mysterious Dr. James Marcus, who bears his own grudge against Umbrella.Zero employs a character-switching system where the player controls both Rebecca and Billy throughout a single playthrough: the player can either 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. The knowledge of when to stick together or split up becomes integral to solving many of the puzzles. The game also eliminates the series staple of item boxes; Rebecca and Billy can instead drop their items anywhere and later retrieve them from the same locations.Zero becamse the last game of this franchise to utilize pre-set camera backgrounds and exploration-oriented game design; Resident Evil 4 marked the series' shift towards action and shooting.
Resident Evil Zero contains examples of the following tropes:
Action Girl: Rebecca, sort of. She's certainly much braver and more capable then her 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 Zombie Apocalypse. However, in The Umbrella Chronicles, we find out she has at the very least had a nap.
Always Close: No matter how quickly you get to Rebecca, she is always saved just in time when she's dangling from a ledge.
And Then John Was a Zombie: Edward Dewey becomes a zombie shortly after being killed by zombie dogs, while Dr. Marcus becomes the Leech Queen.
And Your Reward Is Clothes: 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.
Awesome, but Impractical: 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.
Behind the Black: 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 Scare Chord and Psycho Strings start up.
Big Creepy-Crawlies: 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.
Body Horror: 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.
Chained by Fashion: 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.
Clown-Car Grave: 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.
Rebecca at one point visits the turntable and the entrance to Birkin's lab from Resident Evil 2, 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.
Demoted to Extra: The zombie dogs make just two appearances during the entire game, and only on the train.
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.
Giant Space Flea from Nowhere: 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.
Grappling-Hook Pistol: 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.
The Greatest Story Never Told: The only witnesses to the events of Resident Evil 0 besides Rebecca are the 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.
Hero of Another Story: Inverted when you think about it. As pointed out by Tom Wilde's plot analysis, Billy and Rebecca sort of just happened to wander into The Last Dance between Birkin and Wesker and Marcus and don't actually contribute anything until the very end. In any other context Wesker would be the protagonist (albeit an evil one).
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.
Hidden Depths: Gruff, short-spoken Billy is remarkably talented at playing the piano.
I Can't Use These Things Together: 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.
Insurmountable Waist-Height Fence: 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.
Inventory Management Puzzle: 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.
Invisible Backup Band: 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.
I Won't Say I'm Guilty: Billy refuses to confirm or deny whether or not he really did commit the murders he was sentenced for. 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.
Kill It with Fire: 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.
Let's Split Up, Gang: Can be done by the player as part of the partner system. Some puzzles also force you to this.
Loads and Loads of Loading: 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.
Never Split the Party: 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.
Odd Couple: 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 Teeth-Clenched Teamwork, but they eventually become Fire-Forged Friends after he saves her life repeatedly, proves to be a decent guy, and she lies to her team to protect him.
Papa Wolf: See Odd Couple above; Billy becomes a "big brother" version of this to Rebecca over the course of the game.
Puzzle Reset: 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.
Refrigerator Ambush: A zombie pops out of the refrigerator in the dining car after you've solved a few puzzles.
Roaring Rampage of Revenge: The "mysterious youth"/ 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.
Inverted. At one point, the player has 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 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.
Shotguns Are Just Better: 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.
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 that you need to go through the boiler room.
The Medic: Rebecca, as the field medic of S.T.A.R.S.
Saving Rebecca before she falls, although most players won't realize it unless they wait around long enough.
The final boss fight.
Two-Keyed Lock: More than a few of these around to take advantage of the partner system.
What Happened to the Mouse?: 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.