Revealing mistake: When Alice trips and falls on the staircase, the Woman gets on top of her and tries to stab her. Throughout their struggle, you can clearly see that Alice is in fact replaced by a stuntman. (01:28:00)
Revealing mistake: When Charlie shoots the critter which flies into the air and explodes, we can see the wire the critter is attached to. (01:07:45)
Continuity mistake: When Sam is talking to the P.I about "Taking care of Max," he gets into his car and the window is up. A few seconds later, the window is down. There wasn't enough time for him to roll it down. (00:54:50)