Plot hole: The "video history" of the crashed USAF ship makes it very clear that the planet is uninhabited when they "landed". I can understand how a race of apes develops - they had a bunch of them on board. I can understand how a race of humans develops - they are descendants of the original crew. What I don't understand is...where the heck did all the horses come from?
Revealing mistake: The humans on the planet live a prehistoric existence with little technology, however, they seem to be remarkably good at making foundation garments. Estella Warren spends most of the movie running around in nothing but an animal skin and yet her considerable assets are always held firmly in place.
Other mistake: When the group returns to the lake where Leo crashed, as he is underwater leaving the pod with his pack, he has it in his left hand. The next scene he grabs Estella Warren's hand with his left. The pack is gone. As they swim up, if you watch it frame by frame, the pack instantly appears back around his left forearm before they surface.
Continuity mistake: When the humans are about to be branded the branding iron is in the fire heating up. It stays glowing red hot the whole time Leo is threatening Ari, at least 5 minutes.
Continuity mistake: When all the humans are about to be branded, one of the humans is removed from the cage and the funny old ape just pushes the cage door shut, not locking it. A few moments later the camera pans round and you see that the cage is now bolted.
Continuity mistake: When Leo and his group of rebel apes are starting to ride their horses across the river, the Bonham-Carter character falls off her horse and he swims across the river with her on his back. The other apes can't follow because they're afraid of water. So they arrive horseless. However, when they get across the river, suddenly everybody has horses.
Continuity mistake: When Leo dives in the pond where his pod crashed, to get his bag, it is dark and dingy, yet when you see an underwater shot the water is a clear blue/green colour and you can see the sun (or some form of light) shining through the water, yet when he comes out there is no light and it is dingy again.
Continuity mistake: When Leo gets into the pod to try to catch the chimp's pod, he puts on his helmet. Look away, look back, and he's all snapped and buckled in, which would have taken several minutes at least.
Plot hole: At the very end, when Leo Davidson crash-lands in Washington, DC, on the very steps of the Lincoln Memorial, the modified Lincoln statue depicts General Thade (the founder of the ape civilization on Earth) as wearing mid-19th Century clothing. This suggests that Thade escaped from his home planet Ashlar (aboard the recovered single-passenger Delta Pod, no doubt), entered the time-rift, and arrived on Earth in the early-to-mid 19th Century to begin taking over the human population. So, Thade by himself (with no advanced scientific knowledge) completely conquered human civilization on Earth in only about 150 years, which is absurd even for space fantasy.Charles Austin Miller
Plot hole: We know that Pericles the chimp (in Alpha Pod), then Leo Davidson (in Delta Pod), and then the entire Oberon space station are all pulled into the time rift and end up on planet Ashlar, each arriving at (drastically) different times. Apparently, just before the Oberon crashed on Ashlar, Commander Vasich sent a mayday transmission ("We're going down!") which is actually received by the Oberon itself before it entered the time rift. Commander Vasich and the Oberon crew are startled to see a very elderly Commander Vasich in the mayday transmission. This implies that Vasich and the Oberon crew instantly aged by decades while going through the time rift; yet, Leo Davidson and Pericles the chimp didn't age at all.Charles Austin Miller