Battle for the Planet of the Apes (1973)

The original simian saga ended with a sequel to the Theatrical Cut of the previous film. It's a story of Caesar told in flashback. Twelve years after the end of the human/ape war the two races live side by side but aren't equal. The apes rule. The humans work the fields and clean the apes' houses. There's peace, yes, but it's an uneasy one held in place by fear and one-sided politics.
I suppose it's possible that the entire ape population could've learned to speak by this stage, but it does seem highly improbable.
The script tries hard to inject moments of real feeling by comparing and contrasting the family unit with the civil one, but even when tragedy strikes it doesn't hit as hard as it should have. And while the Kane and Abel element does its job well enough, the whole film feels unnecessary.

1½ paths rebuilt out of 5

Conquest of the Planet of the Apes (1972)

Part four continues the circular narrative, showing the reasons for the bloody revolution that established the ape society as it existed in Parts I and II.
It's interesting that even years later some apes wore the colours of the suits given to them by man. With the emphasis on slavery being what it is, I like to think the filmmakers were aware of what that implies and didn't use it simply as a cheap and easy way to differentiate the ape types.
Conquest probably won't win any new fans on its own merits, but it ought to keep existing ones content. So unless you're already fully invested in the symbolism of the world, then you may want to give it a miss.

3 true colours out of 5

EDIT: the blu-ray has two versions of the film, a Theatrical Cut and a slightly longer Unrated Cut. The two versions differ in how the final act plays out. The Unrated cut is the one that's arguably the more memorable of the two.

Escape from the Planet of the Apes (1971)

The ape japes continue, this time from the viewpoint of the simians themselves. It may be delivered from a different perspective but the analogy works much the same. I'm not going to pretend that the story doesn't require a huge leap of faith from the viewer, but sci-fi has been asking that of fans for a very long time, and once we're able to accept the event in question then the film justifies its existence many times over by exploring a number of deep concerns and raising questions about causality.
Kim Hunter absolutely owns it with her work as Zira, the hot-headed advocate of the truth who satisfies her morals to the detriment of herself.
They could've ended the story here quite effectively. They didn't. Hollywood loves a cash-cow; they'll even milk ape tits.

3½ primitive inquiries out of 5

Beneath the Planet of the Apes (1970)

The principal cast members return to their roles but don't get the same amount of screen time as before. It's not a problem, though, because James Franciscus is an excellent replacement for Heston as the leading man. He plays Brent, an astronaut who's sent into space to determine the whereabouts of Taylor, but, as improbable as it sounds, ends up in the very same place and time.
Overall, it starts good, the first half is excellent, but as the story moves to the 'Beneath' part of the title the film begins to follow suit. It adds a lot of new elements but somehow they lessen rather than enhance the narrative, and it culminates in a half-assed climax with some silly contradiction.

3½ silent affirmations out of 5