Trivia: Star Milla Jovovich has admitted that she can be quite clumsy at times, and evidently had a habit of accidentally hurting cast and crew-members during some of her more intense scenes. The most notable being the sequence when she kills James Purefoy with an ax. Jovovich accidentally hit Purefoy right on the top of the head with the prop-ax. Despite it only being a plastic mockup, the prop-ax evidently hurt quite a bit, and caused a delay on set when Purefoy became quite angry and screamed at Jovovich, despite Jovovich genuinely and profusely apologizing repeatedly for the mishap.
Trivia: Anyone else notice that all of the team have arm patches that say 'Sanitation'? Its most obvious when One is walking through the Laser hallway. (00:13:04)
Trivia: The bodies of the dead mercenaries disappear from the laser hallway a few scenes after they are killed, which is commented on by one of the characters. Although the implication is that they were likely taken by zombies or one of the Licker creatures, this scene is actually also sort-of a cheeky in-joke for video-game fans. In most video games, the dead bodies of enemies will either disappear after a short time and/or completely vanish when the characters leave the room/area. This is done for technical reasons usually to help the game run smoothly by not having to use too much memory on constantly generating dead bodies on the game-map. Hence, the filmmakers decided to include this scene as a reference to this in-game phenomena.
Trivia: The "Resident Evil" video-games were heavily inspired by George Romero's "Living Dead" horror films. Romero was actually brought into production early on as a potential writer-director for this adaptation, though the studio passed on his script. Romero has stated that he heard everyone involved in the production liked his script (which was more true to the game series than the finished film), except for one producer, who wished to take the film franchise in a different direction than the games. This one producer held out for a different take, and refused to pursue Romero's script.
Trivia: As originally intended by director Paul WS Anderson, this film was written to take place in the same continuity of the game-franchise, but serve as a side-story, so he could tell his own tale inspired by the game series without having to do a direct adaptation or change anything too much to match his vision. He later decided that the films would be set in a different canon/continuity than the games, so he could start incorporating his own altered versions of characters and stories from the games.
Trivia: The original voice-actress portraying the Red Queen was briefly recast during production, as the producers and director were unsure if some audiences would be able to understand her young voice and obvious English accent. Alternate versions of her dialog were re-recorded with a new, louder, clearer-sounding American actress. However, much of the cast and crew were uneasy with this new actress, feeling her American accent and much more mature voice made her playful and taunting dialog sound much more suggestive and even borderline-erotic in tone (particularly the line "I've been a bad, bad girl"). Thus, the decision was made to go back to the younger, more innocent-yet-menacing original voice actress.