A very interesting premise, which is why I watched the movie. However, from the first minute the movie doesn't offer anything beyond novelty value. The plot is pretty random and pointless and seems set up mostly to shock the audience. Many scenes which, while aiming to shock, made me just roll my eyes.
Even the main idea - people behaving like they're in the Stone Age - doesn't work well. The people involved live in modern home with modern technology, yet eat with their hands and don't appear to have any degree of intelligence. The concept was not grafted seamlessly into modern life at all.
End result is an absolute mess. Even worse, it's a pretentious mess. One of the worst movies I've ever seen (and I've seen over 5,000 movies).
If you think about it, aren't most human dramas just about power plays and masturbation? Aaaaaaaah! just cuts the shit and, with a wink and a nod, gets right to it.
All the characters have been reduced to ape like behaviour, so they all speak in grunt instead of clear dialogue. Despite this, there is a story between all the characters and tons of social commentary to boot.
For absurdists and fans of random humour and shock, "AAAAAAAAH!" is your saving grace. As Monty Python used to put it: "And now for something completely different".