This movie didn't get great reviews and didn't do well in theatres, but I thought it was great. It could have been better, but anything with Michael Cera starring and Harold Ramis directing deserves a chance.

One problem is the usual Jack Black overacting and silliness. If he toned it down a little the effect of his comedy would be that much more powerful. He should look at the understated passive aggressive method of Michael Cera's acting for some tips. The guy is a genius (Cera, not Black).

Otherwise it was an irreverent look at humanity's past both evolutionary and biblical. Reminded me of "History of the World part 1", though that might just be because of the Roman army costumes.