Other mistake: The crest of the clone trooper's helmet, when he points out that the cannons are being destroyed, does not reach down to the eyeslit, whereas it does with the others'.
Drowsy: Experiment 350 - S1-E39
Other mistake: Pleakley reacts to Jumba's "Where is my experiment?" too early.
Other mistake: Tails automatically knows Cosmo's name even before she introduces herself later on (English Dub version only).
Other mistake: Beast Boy and Wildebeest fight in a cage suspended in an endless room, with no solid ground underneath. But during the fight both combatants keep stepping onto the gaps formed by the cage bars without their feet falling through, as if the cage bars on the bottom side are merely painted onto a solid surface. For instance, watch Beast Boy's feet when he turns into a skunk.
Other mistake: In the scene where Raphael and Michelangelo report from their ceiling vantage point, we see a hallway full of Foot ninjas. Strangely, we can see a brief shot of an Earth Protection Force trooper walking peacefully among amongst the Foot even though they are hostile to them. (00:07:50)
Other mistake: When Turbo-Jet steals the book, it is inside a glass case. Peter arrives, kicks him in the head and he drops the book. When the book lands on the ground, the glass case the book was inside shatters, causing pieces of glass to land on the ground, surrounding the book. A couple of seconds later, when Peter picks up the book, there doesn't appear to be any glass on the ground underneath the book, even though it wouldn't have been able to go anywhere else. (00:07:37)