As Dr. Cutter's date pours wine, the wine bottle swaps from her right to left hand.
When Duane is sleeping, Belial opens his basket and looks at him. The basket lock latch disappears and reappears.
When the guy steals Duane's basket at the movie theater, he kicks the lock off, including the latch. But in the next shot, when Duane runs into the bathroom, part of the latch is still connected to the basket.
The No Fume sign in the hallway goes from straight to crooked back to straight.
Duane's money that was left in the room goes from loose to in a rubber band when the detective finds it.
After Sharon is killed, you can see her clearly still breathing as she lies nude on the bed.
After Duane's father was killed, the fake legs fell on a rubber mat, which was clearly visible.
When Casey returns to her room (where Belial is waiting), she takes off her shoes, changes into her smiley face nightie, strips off her underpants, and goes to bed naked from the waist down. When Belial chases her out of her room, she is wearing control top pantyhose and wedge sling back sandals with the smiley face nightie.
When Belial tears Dr. Kutter's tongue out, all the fake blood can't cover the tongue that's obviously still there, and in following shots, not even covered in blood.
When Casey enters Duane's room to drop him off after he drinks a lot she proceeds over to the basket. By the basket is the file Duane and Belial retrieved after the first kill. On it is blood that is still red. With the amount of time that has passed it should have dried up and been maroon.
At around 7 minutes when Casey is going into the room there is a laughing sound but her mouth is closed.
During the bar sequence, Duane refers to his brother, calling him Duane, instead of Belial.