There are serious errors in the depiction of certain species: 1) The species of humans in the main tribe are supposed to be Homo Sapiens, but they resemble Neanderthals much more closely (Ron Perlman looks like a Neanderthal even without the makeup). 2) Homo Sapiens weren't in Europe 80,000 years ago - they were still making their way out of Africa. 3) The tribe they are attacked by are supposed to be Neanderthals, but they're some sort of hairy ape-creature that had been extinct for over one million years before this film is set (80,000 years ago). 4) There were no saber-toothed cats in Europe at any time. Saber-Toothed cats evolved in North America, then spread to South America during the Great American Interchange (when the Isthmus of Panama rose from the sea and connected North and South America). There *were* very large cave lions (Panthera Spelea) in Europe, but they had the regular dentition of modern African lions (Panthera Leo).
Early in the movie when the Ulam tribe is being attacked from the cliff above there is a tire clearly visible in the foreground in two shots on the cliff top; the first as a shot showing right after the boulders being pushed over the cliff and then again when the Ulams come up to meet them.
In one scene, when they are at the top of the mountain, in the background you can see a vehicle moving amidst the jungle from right to left side of the screen. You have to look very closely, it's very small and can barely be noticed. Sorry. i forgot to note the time but it's somewhere between 54:21 to 55:10.