Revealing mistake: When Ongaro is pushed up against the spikes on the cell bars, the spike against his neck is shown wobbling like rubber. (01:18:50)
Continuity mistake: When the Apes are trying to break into the mutant's church, Mendez looks towards the Alpha/Omega bomb, and is wearing a cream-colored jumpsuit with a purple sash. When the Apes do break in, his sash has disappeared. (01:25:50)
Revealing mistake: When Brent is shot dead, the blood pack is visible on his chest, poking out from under his bandaging. (01:29:15)
Other mistake: As Taylor is dying, there is blood on his hand. When his hand lands on the bomb's detonator after he dies, his hand slides off, but no blood is shown on the detonator. (01:29:35)
Deliberate mistake: There are no lights ever to be found in the underground world and the ceiling is literally the surface's ground, but there is still a perfect level of lighting regardless.
Other mistake: Near the beginning Taylor gives Nova his dog tags. Where did he have these during the whole first movie that they were never found, and why would he have hidden them?
Revealing mistake: Linda Harrison's metallic dental implant is rather noticeably visible during her closeup on her signature line, "Taylor!"
Other mistake: As Taylor realises what man did in the years from his leaving until his return, he is slamming his fist on the dirt screaming "Damn you all to hell." In the first Apes movie, he didn't give this final line until he was amid the surf waters, but here the water was a couple feet from him.
Continuity mistake: The opening is a repeat of the ending of the first Apes movie. In the dialogue between Zaius and Taylor, Taylor turns the horse toward Cornelius twice.
Chosen answer: The mutated humans (the ones with the bomb) have telekinetic powers and projected the image into Taylor's mind, the same way they did with the fire with the apes.
Bishop73