Mr. DuLac’s review:
All knowledge is for good. Only the use to which you put it can be good or evil.
Easily my least favorite Planet of the Apes film from the originals. Paul Dehn's vision for the screenplay being compromised is probably it's biggest problem with the limited budget being the next. If you watch the special features on the DVD/Blu-ray you'll see what Dehn's original concept for this film was, complete with original title: Rise of the Planet of the Apes. Combined with the original ending of Conquest of the Planet of the Apes this could have been the darkest sci-fi franchise ever.
It's pointless to dwell on that though, what you get here is still a fun campy sci-fi film. The direction of the social insights might surprise a few after seeing the tone of the four previous films however, and for me the ending almost seemed like a cheat... like it wasn't the proper ending for this franchise.
The movie's saving grace is seeing Roddy McDowall as Caesar. Having McDowall playing an ape one last time is worth watching the film alone. He doesn't have much of a character arc like Conquest of the Planet of the Apes, but he still plays the character with heart.
It might not be the ending I would have preferred, but it's still a fun film to watch and part of a great larger story.