This is the first Resident Evil game to use fully polygonal backgrounds, where as the previous games used pre-rendered backgrounds.

In the basement of the torture room, where you get the piano scroll, there are four statues. They carry a sword, a helmet, an armor and a shield respectively. This is a reference to the decoration on the four keys that were used in the Mansion in Resident Evil (1996).

This is the last canon Resident Evil game release to use the name of actual guns.  All Resident Evil games (Resident Evil 4, Resident Evil 5) after this use made up names such as Broken Butterfly, Black Tail, Jail Breaker, L. Hawke just to name a few examples.

In the locker room of the game, the player can find a vending machine with the words 'Valentine's Rosso' on it. Both of these are surnames of characters found in Resident Evil 3: Nemesis, with the former being of the main protagonist Jill Valentine while the latter refers to Dario Rosso, a man Jill finds at the beginning of the game.

In this game, the virus that mutated the residents of Rockfort Island and Antarctica isn't the T-Virus, it's the T-Veronica Virus. In-game files reveal that the Ashford family created the T-Veronica Virus by injecting viral genes found inside an ant queen's DNA into the mother virus (the original virus that was also the basis for the T-Virus).

Steve Burnside's image is modeled after the late River Phoenix, and Leonardo DiCaprio.

This is the first Resident Evil game to take place internationally, and not in Raccoon City, because of the city's destruction. The initial setting, Rockfort Island, was long assumed to be located in the South Pacific (based on the Prisoner's Diary stating that it is "far south of the equator"), although some claimed it was near the coast of Europe. It was finally revealed in Resident Evil: The Darkside Chronicles (2009) that Rockfort Island is indeed in the Pacific Ocean, off the west coast of South America.

During the early development stages of the game, Jill Valentine was supposed to be the main character. Alfred and Alexia Ashford were named Hilbert and Hilda Krueger respectively; they were the children of an old Nazi officer who had fled Germany in an old submarine after WW2, and made his base on the island. The game also featured a butler who was an old army friend of his Hilbert's father. Jill Valentine was changed into Claire Redfield because Resident Evil 2 (1998) had ended with the implication that Claire would return in the series. The twins were rewritten as British nobility because the writing team thought that references to Nazis would hurt the game's commercial chances in Europe; the butler was only kept in in-game file references.

The DreamCast's release included a non-interactive DVD titled Wesker's Report, which keeps the fans up to date on the story of the series.  This is only available in the Japanese version, but some people ripped the DVD and uploaded to YouTube for the world to see.

Alfred and Alexia Ashford were both born in 1971. This is also the password used to access Alfred's secret mansion.

The game takes place about 2-3 months after Resident Evil 2 (1998) and Resident Evil 3: Nemesis (1999).

Was given an HD remaster for the PlayStation 3 and Xbox 360 in 2011. This includes some slight texture update, widescreen, 720p and a softer and deeper color overlay.

During the Battle Mode in the original Dreamcast version of the game, if you use a scope to look between a container and a set of drums, you can see a motionless Rodrigo Juan Raval standing on the other side. This feature was removed from the 'Code Veronica X' version on all subsequent platforms.

Parts of the mansion found in the Antarctica Facility are almost exact replicas of the Spencer Mansion from Resident Evil (1996). Note the main entrance hall, art room and the L-shaped corridor. A memo from Alexander Ashford reveals that his Antarctica Mansion has a room "similar to the design of [his] mansion", and it is the legacy of "the late Trevor". The room he refers to is the hallway containing the twins' bedrooms, which are identical to the rooms in the mansion on Rockfort Island. The man called 'Trevor' is George Trevor, the architect who also designed the Spencer Mansion in Resident Evil (1996).

The differences between the standard DreamCast version and the X PlayStation 2, plus all other future Resident Evil CODE: Veronica X releases, is more features.  Such features include added scenes: Claire meets Wesker outside the palace doors; a fight between Wesker and Alexia and a new ending including a fight between Chris and Wesker, where Chris gets taken down easily. 

This is the only canonical Resident Evil where the playable character is incapable of wardrobe changing.

This is the first Resident Evil game where you get to play as three separate characters within the same main game. The game alternates between main characters Claire and Chris Redfield, and there is one short sequence where you control Steve Burnside. Previous games in the series never allowed the player to control more than two characters: one main character and one that is briefly playable.

First game where Chris mentions Leon.

Although they have become widely known within Resident Evil lore, the name of the prison island and Steve's last name are not even once mentioned in the main game, nor referred to in the main game files. Only in the Battle Mode minigame can a hidden file be found that identifies the island as 'Rockfort Island', and when selecting Steve in the Battle Game, his last name is revealed to be 'Burnside'. Additionally, the wounded guard who frees Claire in the beginning is never named in the entire game. The Dungeon Mode minigame in Resident Evil: Survivor 2 - Code Veronica (2001) identifies him as Rodrigo Juan Raval.

The yellow Tyrant-like creature with one oversized arm is called a Bandersnatch, named after a creature mentioned in the poem 'Jabberwocky' from Lewis Carroll's novel 'Through The Looking-Glass'. Although no detailed description of the creature was made in the book, it has an extendable neck, while the Bandersnatch in Code Veronica can extend their arm.

The last Resident Evil game to be released to the defunct Sega DreamCast.

Apparently, Leon S. Kennedy from Resident Evil 2 (1998) was at one point slated to appear in the game, judging by an article on IGN stating that Paul Haddad, who voiced Leon in Resident Evil 2, was at the time listed on IMDb as voicing Leon in Code: Veronica (and subsequently removed). In the finished game, Leon is briefly mentioned but makes no appearance. One fan theory states that the creators decided to change Leon to a new character called Steve Burnside late in development, so the existing character designs and animations for Leon were slightly altered, explaining why Steve and Leon look a bit alike.

Despite the fact that in the end, Wesker claims that his men have taken the infected Steve, Steve is never seen or heard from again in any future Resident Evil games. The game Resident Evil: The Darkside Chronicles (2009) later revealed that Wesker harvested a T-Veronica sample from Steve's body, and sold it to a South-American drug lord named Javier, as a cure for his diseased daughter. The "Lost in Nightmares" scenario from Resident Evil 5 (2009) also contains some new monsters that resemble the mutated Steve, suggesting further experimentation with the virus.

Although Steve Burnside is mostly a supporting character, he is briefly playable during the campaign. This makes him the first (and one of the few) playable character in the series to die during the main game as part of the narrative (thus excluding 'game over deaths').

First game in the series to have a super human Wesker. Prior to this, Wesker did not have any super human abilities. The short video Resident Evil: Wesker's Report (2001) (released with some copies of the game) revealed that Wesker had injected himself with a special virus from William Birkin shortly before he was killed by the Tyrant in Resident Evil (1996) (remade as Resident Evil (2002)): "If I made Umbrella believe I was dead, it made it far more convenient to sell myself to the opposing corporation. The virus had profound effects. It would put my body in a state of temporary "death." It would then bring me back to life with super human powers. Therefore I unleashed an awesome Tyrant from its slumber and let it attack me."

The game reveals that the Umbrella Corporation was founded by Lord Spencer (whose mansion was the setting in Resident Evil (1996)) and Edward Ashford to mask their biological research. The third founder, James Marcus, isn't mentioned or revealed in the series until the series' prequel Resident Evil Zero (2002); due to a power struggle with Spencer, he was executed by Albert Wesker and William Birkin on Spencer's orders, long before the events of the game, explaining why he has never been mentioned since.

In the game's Battle Mode, a secret document called 'D.I.J.'s Diary' can be recovered from one of the slot machines. The diary describes a person's point of view throughout the game, as they witness key events such as the encounters between Claire and Chris Redfield with Albert Wesker, and Claire's battle with the Tyrant.

When their climactic fight is cut short, Wesker tells Chris: "Until we meet again". This sets up the events of Resident Evil 5 (2009) where they have their final battle with Wesker being mutated by Uroboros and killed by Chris.

Hidden animations: there are extra death scenes for killing the Nosferatu monster with either the sniper rifle or the knife. If you shoot him through the heart with the rifle, Claire can be seen aiming, shooting and saying "I've got you now!", and the creature collapses. If you finish him with the knife, the same happens as she plants the knife into his heart. None of these cutscenes appear if you finish him off in any other way.

Actions performed in one scenario can have consequences for later ones. For example, if Claire gives Rodrigo a hemostat medicine, he will give Chris a lighter in Chris' scenario (after saving him from the worm). If Claire leaves the fire extinguisher in the prison security box instead of an item box, Chris cannot use it later to obtain a Magnum. Most importantly, if Claire is poisoned by the Nosferatu boss, then Chris will have to retrieve a serum to cure her.

Sequence breaking: when Chris restores the power and lifts Alexander's body from the ice with the crane, Alexia will show up and send the giant spider on him. However, if Chris frees Claire in the Antarctica mansion and then battles with Alexia first, then Alexia will not show up at the spider fight.

In Claire's first scenario, she releases an infant albinoid that escapes the lab. She also finds information that states that the Albinoid can fully grow to 7 feet in about 10 hours. Given the fact that the same Albinoid encountered in Chris' first scenario seems fully grown, it would indicate that Chris' storyline occurs at least 10 hours later than Claire's.

In the original Dreamcast version of the game, Claire Redfield and Albert Wesker never meet. The more widely known 'Code: Veronica X' version of the game adds an early meeting between Claire and Wesker, and a second encounter during the extended finale. Chris and Wesker meet once in the original version, and three times in the extended version.

The Giant Worm, the Adult Albinoid and the Giant Spider are the only boss fights that can be skipped. Claire can actually kill the worm in her scenario, but it will still show up in Chris' scenario, not in any way affected by Claire's efforts. Tyrant Steve cannot be killed; running away from him is all that Claire can do to beat him.

The game's soundtrack gives a clue to a code towards the end of the game. One track title is "The Code Is Veronica" and it plays the music from the section of the game where you enter a code (VERONICA) to activate the self-destruct system and open all the electronic doors before the final fight.

Alfred dressing up as Alexia and talks in her voice is a reference to the Alfred Hitchcock movie Psycho, where a young model owner dresses and talks like his dead mother when he kills.

Mistakes

When Steve saves Claire from the Bandersnatch, he fires over 30 bullets with his two Luger pistols without reloading. Lugers can only hold up to 8 bullets per clip. Steve shouldn't have been able to fire more than 16 rounds at most.

It doesn't snow in Antarctica, at least not very often.

When Steve shoots at the monster attacking Claire, he fires his twin Lugers at the monster at a rapid speed. Yet, the moment the player controls him with the Lugers during the combat mode mini-game, Steve fires the Lugers at a slow and ineffective pace. Also, the monster he does shoot is severely affected by the bullets during the cut-scene, but during combat, the creature is able to move and even attack once hit by the Lugers.

Claire and Steve walk around the outside of Antarctica wearing nothing but their shirts and jeans without succumbing to the extreme elements and dying of exposure.

Obviously the scene where Steve shoots the monster attacking Claire could not have happened as it did: Steve would have been injured by breaking head and shoulder first through a large pane of glass and he would not have been able to shoot the monster and hit it accurately without looking at it first without recovering from the fall.

The twin pistols Claire kills a zombie for early in the game are Calico M100P, but are not 9mm as the game says. In reality they're chambered in the .22LR cartridge.

Claire and Steve are Americans, but information about them is measured in metrics, where as Americans don't use the metric system.

After Claire and Steve discover that Alfred Ashford dresses up as his twin sister Alexia and pretends to be her, Claire states "So there never was an Alexia after all," despite having previously seen a home movie that features both Alfred and Alexia when they were children in the screening room, and on Alfred's computer in his office.

The bow gun fires faster than one can possibly shoot.

It's never really clear why Albert Wester freaks out and tosses aside Chris Redfield, the man he's determined to kill for revenge and has firmly in his grasp, when he hears Alexia laughing on the computer monitor. He obviously knows that Alexia is in Antarctica and not on Rockfort Island.

When Albert Wesker meets Claire Redfield for the first time, he explains that he was the one who led the attack on Rockfort Island and is overjoyed about Claire still being alive as it guarantees that Chris Redfield will come to save her, allowing Wesker the opportunity to have his revenge and kill him. But what makes Wesker so sure that Chris Redfield will come to the island to rescue Claire. He doesn't know that Claire had sent a message to Leon to inform Chris about her whereabouts. For all he knows, she may not have had any means to send word of her location to Chris yet. This plot hole is not present in the Dreamcast version as Wesker never encounters Claire Redfield at any point in the story.

The opening scene that shows Claire's capture has her somehow avoiding death by machine gun fire coming from a pursuing helicopter. Yet the machine gun is mounted on the left side of the helicopter which is pointed directly at Claire's side as she's running from it. Simultaneously, Claire is able to out run the helicopter as it is strafing after her.

When Claire Redfield raids the Umbrella Facility in Paris, she dives into a basement to escape the attack helicopter only to find it's full of Umbrella security guards all ready and waiting for her. How did they know that she would head into the basement, she could have easily been shot to death by the helicopter or taken a different corridor to evade its gunfire.