Audio problem: When the mysterious lens flare creature possesses the microwave oven, its door opens with a disproportionate "creaking door hinges" sound effect. Inherent phoniness aside, the noise is also continuous, but if you look at the door, it did not open in one fluid motion; the actor's pelvic thrusts as he was boinking the stewardess got in the door's path for a moment putting it to a momentary halt. (00:14:05)
Audio problem: When the boys are in the club, as the music comes on just before they start dancing to their song, we hear Dustin say, "I don't like this song", but his mouth movements don't match that sentence.
Audio problem: After Conrad and Sally push the cat over the fence, the cat says, "Alright, Nevins, time to die." Then, as Conrad says, "Cat, you scared him away," the scene is poorly edited, as it cuts back to Conrad and Sally going over the fence, and Conrad makes a noise as the line plays aloud. (In a deleted scene, as Conrad says, "Cat, you scared him away," it simply cuts back to the cat as Conrad says the line behind the fence.)
Audio problem: When the cops get into the gun shop to buy some weapons you see a police officer on the left loading a M4 (or checking something) but you never hear the sound of this action.