Revealing mistake: Rudy's "Judgment of Glory" Finisher uses a special background of distant mountains and cliffs. Sometimes (in particular during Mecha Goenitz's challenge) part of energy/fire or even whole enemies get in front of the superimposed image, casting shadows on it like a cheap theater background.
Revealing mistake: Baxter Building: Just as Captain America and Mr. Fantastic are about to land on the ground after jumping off the Helicarrier, Captain America's shadow doesn't match up with his distance off the ground.
Revealing mistake: In the last midtro for level 18, "Mount Doom, " Sam reaches down to pull Frodo up the edge of the walkway. Sam's hand is seen to the top right of the screen, but a good chunk of it is missing.