Continuity mistake: As the giant mosquito flies toward Mr. Davis, Davis has the remote control which controls the mosquito hanging around his neck. In the very next shot the remote control has disappeared.
Continuity mistake: When "Tina" ties up Bud in his wheelchair, she puts a belt around his body. The belt shifts/rotates around his body between shots (you can tell by a patch on the belt, which moves around).
Continuity mistake: When The Possessor puts a mask of Toby on, in front of Maggie, he then takes it off and puts it on a metal tray. He then takes a second mask and puts it on. then, when he goes to put the second mask down, the mask of Toby, which he left on the tray, is now placed on a foam dummy head.
Plot hole: When Toby is checking everyone to make sure their costumes work, wheelchair-bound Bud is shown standing in a coffin-fixture. Since he was in the coffin costume, there was nothing there to be "holding" the character in a standing position, and he was obviously not in his wheelchair, as he is at standing height with everyone else.
Continuity mistake: When "Tina" places the tape recorder down in front of Bud, the black strap on the tape recorder is on the left side in one shot, but in the next shot it is on the right side.
Continuity mistake: When 'Tina' is attacking Bud, she puts tape over his mouth. In one close-up, the bottom of the tape is folded up, revealing the bottom half of his mouth, but in the subsequent wide-shot, the tape is perfectly neat, and unfolded, covering the whole of his mouth.
Visible crew/equipment: In the montage, where the group are getting Dreamland prepared for the Horrorthon, in one shot we see Bud fiddling with the electronic box (which is unplugged). As the camera pans backwards, you can see the shadow of a crew-members head wearing headphones, cast on the electronic box.