That movie also depicted four species of hominids interacting, one of which, the large bodied cannibal eating their captured Homo Sapiens, has never been found in the fossil record. The hair-covered species that evicted the Neanderthals from their cave in the beginning of the movie had disappeared at least a half-million years before the time the movie allegedly depicted.
You say it's "classic", I say it's no more than a fantasy movie. Especially the scene where the Neanderthals were confronted by a group of Mastodons that accepted the offering of a handful of grass on the steppe (?) and left them alone.
Hey, gimme a break, it's a movie, not a documentary. It was memorable, which is more than you can say for 99% of the dredge coming out of Hollywood these days. Not a single word is spoken in the entire movie, and yet it still holds your attention. My wife hated it, though...lol.