Continuity mistake: When Mickey is being interviewed for the yearbook, watch out for students that walk in his opposite direction. There are obvious recycled extras appearing in multiple shots coming from the same direction, such as the blonde with checkered top paired up with a guy in a blue shirt. (00:09:00)
Continuity mistake: In the cabin, the survivor and Howe hear an explosion, and the survivor goes out to investigate. He pulls up a board and unlocks the door, and only closes it after him. When the girl comes up from the basement, the door is closed, locked, and barricaded.
Continuity mistake: When Lloyd wheels out his camera and begins filming, you can see that it's a Betamax. When the cute little kid holds up the video tape produced by that camera, it's a VHS tape. (You can tell because it fits neatly inside the box. Beta tapes were entirely different dimensions from VHS and a Betamax wouldn't fit in a VHS box.)
Continuity mistake: When the men posing as painters rip off the drug dealers, they place a scaffolding plank to cross to the other building, which they remove from the windows and it falls onto the street. When Chuck Norris enters the apartment it reappears.