Other mistake: During the Pokérap, when the Poliwrath name is said, the Pokémon shown is actually Poliwag. Also, when the Graveler name is said, the Pokémon shown is actually Geodude.
Revealing mistake: We can see Ecliptor's zipper from behind - slightly revealing on Saban's part, considering Ecliptor is supposed to be an evil monster henchman of Astromena's.
Continuity mistake: When Kung Lao and Shang Tsung are preparing to fight each other at the tournament, watch Shao Kahn. He gets up off his throne, then it cuts to wide shot and he's sitting down again. Then it shows him standing up again only to go back to sitting down a fraction of a second later. (00:03:40)
Revealing mistake: When Pablo as the ping pong bandit takes Tyrone's paddle, Tyrone asks if he can play Pablo again so can get his paddle back. When Pablo walks into the frame, his skin clips out of his coat. This also happens when he does the "Bandit Slammit".
Winning Through Intimidation - S1-E15
Continuity mistake: Panik's Metal Guardian can be seen on the field several minutes before he actually plays it. (00:10:30 - 00:13:00)
Plot hole: During the episode "Superstition", Onizuka thinks he has cancer because the magnetic pain-pads he was wearing created strange blobs in the X-Ray he has taken. However, given the fact that the X-Ray was so strange, doctors would have given him a complete physical, and noticed the pads much sooner. Here, they literally just assume he has tumors, and fail to ever take notice of the pads. Simply impossible, given the gravity of the situation. (Obviously, this is to pay off at the very end of the episode.)
Continuity mistake: In the episode "Fool's Gold" Debbie puts the fool's gold on top of the pail on her sculpture. The shot changes and it's gone, the next shot it's back.