Continuity mistake: Near the end of the film, on the train ride out of the Hive, Rain is quite close to becoming undead. When she speaks, we notice her teeth are still "movie-star white". However, a few shots later, when she becomes a zombie, she sort of hisses where you can see it has taken what couldn't have been more than a few mere minutes for her teeth to become brown and discolored.
Continuity mistake: Near the end, when Alice, Rain and Matt are talking to the "Red Queen" in the virus lab, there is a wall-mounted LG Flatron TFT display where the Red Queen shows surveillance footage, etc. One can see an inventory type barcode label in the bottom centre of the screen. The camera cuts away briefly, and when the camera shows the display again, the barcode label is gone and the LG logo is in its place.
Continuity mistake: When Alice escapes the first zombie dog and locks herself in the room, a zombie approaches her and she kicks him down. When the zombie falls you can see his tie is partially outside of his suit. When it cuts to Alice reaching for his gun, the tie is tucked inside his suit.
Continuity mistake: The way the T-Virus capsule hits the ground is the same each time they show it, however when it's on the ground and motionless, the position is changes. During the flash back at the end that Spencer is having, the capsule is all over the place. However at the beginning, the capsule is just in a little straight pile on the floor.
Continuity mistake: Shortly after the Licker pulls Kaplan out of the train, Matt shuts the door so it can't get at the rest of them. The Licker goes on the roof to use the back entrance to get into the car. Matt hears this and rushes to bar the back door. Pay attention to the near dead Raine. She suddenly gets a lot more life and quickly moves out of the way to avoid being accidently trampled.
Continuity mistake: When Matt is at Lisa's desk he looks through some papers, he is looking at a paper which has black squares on it. Then he puts the paper down and looks at another paper. When it cuts to him noticing Lisa approaching he is now holding the paper with the black squares again.
Continuity mistake: On the train, just after Spence falls in, Alice takes off her wedding ring and sees on the inside: Property of Umbrella Corporation. However, after she finishes off Spence, she drops the ring next to him, and in that shot, the inside is clean; or at least the half we can see when it lies still. Such a long line would take up a lot of room on such a small ring in that size text.
Continuity mistake: When Alice and Matt run to meet up with Spencer, Kaplen, and Rain, Alice screams "Don't shoot!" and Spencer, Matt, and Alice try to close the door from the zombies. A zombie then grabs the inner part of Spencer's arm, then a shot moves showing the zombie holding onto Spencer's arm from the bottom, then back to the inner part.
Continuity mistake: In the scene where Matt pulls Alice into the mansion at the beginning of the movie and the SWAT team comes through the windows, the main SWAT member pulls Alice aside and asks for her report. If you watch the scene Alice has one arm at her side and one across her chest. A split second later it shows her reflected in the eye lenses on the SWAT member's mask and Alice has her arms crossed in front of her. Another split second later they show Alice again and her arms are in the original position.