After MTV is insulted, Gonzo spits out his mouthpiece onto his giant nose-ring. When it cuts to the other character he's talking to, it's gone. When it cuts back to Gonzo, it reappears. This happens several times throughout their conversation.
The green fluids on Dewy Martin's shirt and mouth changes in variation.
When Dewy dives out the classroom window, he falls front first toward the ground; yet he lands on his back.
Gonzo crashes into a cake offered at high school's bake sale; most of it disappears from his body.
When Warren walks to his house, he stumbles around until he reaches the stairs. By the next shot, he's stumbling around in the driveway again.
The ambulance that picks Chrissy up from the high school, though bringing her to local Tromaville Medical Center, clearly says MEDICAL CENTER Jersey City on the back doors.
When Warren is drooling green ooze from his mouth, you can already see dried up green dye all over his shirt from previous takes.
Obvious reverse action of the monster baby throwing dishes out of the sink; you can tell by the soapy foam moving on the sink.
In the cafeteria, the discussion about the college party says it is being held by the Pi Delta Gamma Fraternity. When the Greek letters at the frat house are viewed, they read Phi Gamma Delta.
Even though Dewy drools green foam from his mouth, none drip onto the student he's strangling.
The Tromaville Welcome sign can be seen in a few different places in the film.
After the woman's handbag is stolen, she screams but her mouth also moves.
(around 50 min.) When the Cretins are attempting to drown Warren in one of the bathroom stalls, there's a large silhouette on the stall wall that reveals the cameraman's shadow.