Revealing mistake: Blank firing adaptors are visible on the bow machine guns of Oddball's Shermans as they shoot up the rail yard. (01:00:05)
Revealing mistake: The cannons shown are firing blank charges, which produce no recoil. Recoil has been simulated by towing the guns backwards when they fire. The problem is, there is always a distinct delay between the discharge and the "recoil." The cannon also seem to largely fire explosive shells. At no point do we actually see a cannon ball rolling or bouncing along the ground or into any group of soldiers.
Revealing mistake: When Ursus is giving his speech in the Ape city, many of the Chimpanzees and Orang-utans are wearing incredibly fake-looking masks. (00:17:15 - 00:19:50)
Revealing mistake: As the final chase for Deke starts, Ed tosses a wicker basket at Iris. The toss is already pretty weak looking, but to make matters worse, Judy Pace tosses the gun on purpose in front of her a moment after being 'hit'. (01:28:55)