Continuity mistake: Right after Bennett takes off in the plane, Claire throws a gun to Alice. Between the slow-motion shots, the gun switches position in mid-air before Alice catches it. In the shot of Claire throwing it, the barrel is facing to the right, meaning that it should be facing to the left in the shot of Alice catching it. But it still faces the right when she does.
Continuity mistake: When Alice makes the first approach to land on the roof of the prison, Luther shouts "Down!", and they all duck. In the close up shot of the group, you can see that Angel and Bennett are facing the same way as Luther and Kim. But in the wide shot, they are facing in the opposite direction.
Continuity mistake: When K-Mart throws Alice's shotgun to her right before she shoots Wesker in the mouth, between the slow-motion shots, the gun switches position in mid-air before Alice catches it. K-Mart throws it with the barrel facing towards Alice but when she catches it its barrel is facing away from her.
Continuity mistake: During the scene where Bennett takes off in the plane, the concrete edge suddenly disappears. He hadn't already taken off, because he makes a huge dive directly after leaving the roof, and even if he did use it as a ramp, then it makes no sense why Alice did smash through the edge.
Audio problem: Near the beginning of the film when Alice and her clones break into the Umbrella building, she comes down in an elevator. The numbers above the elevator showing what floor she is on beep every time they change, but some of the beeps are out of sync. A beep is heard for floor 6 before the number 7 has even changed and a beep is also heard a fraction of a second before the number 3 fully appears.
Continuity mistake: During the scene on the rooftop, after shooting some approaching zombies, the group run into the lift while shooting a bunch more zombies. The bomb then explodes, sending the lift down. The scene goes back to Alice fastening herself on a sling. When the camera moves to show the zombies, all of the zombies have moved back some 25 feet away and all of them are standing still, waiting patiently for Alice to make the next move. Alice turns around to run to the edge of the building, and we can see that the zombies who had been shot earlier and should still be lying around have magically disappeared.
Factual error: Alice isn't superhuman in the scene of the Tower Swing. But at the rate she is falling, she would both hit the ground before the cable would be under tension, and even if the prison was high enough, it would probably shatter every bone in her shoulder when it does become tensioned.
Continuity mistake: During the initial fight scene, the clone who survives the Needle Dive is later on shot by Wesker, upon which she drops two grenades. Where did she pull those grenades from? Right before she jumps out of the window, you can see that there are no grenades dangling from a belt, and there isn't much room to hide something like that in a skintight catsuit.
Factual error: In the scene where Alice lands the plane on the roof of the prison the length of the roof is far too short to have landed in that distance at the speed they were traveling. The wings also impact several solid objects during the landing which would have damaged them, if not severed them completely. At the end of the landing the nose smashes through a solid concrete ledge at the end of the run. The propeller is too fragile and should have shattered in an impact that forceful but instead remains completely unscratched.