Visible crew/equipment: When Martin is fighting the "puppy" at the door, you can see a crew member's hand pushing the doorknob open to portray the puppy is trying to get back into the room.
Continuity mistake: Everyone drops to the ground and ducks when they believe that they heard gunshots. The microwave beeps and Tommy says it's just his popcorn. When he takes the bag out it is white, but immediately afterward it is red. (00:13:20)