asterisk8 said:
Anyone who want a GOOD critique of the film that explains what's wrong with it from someone who knows what he's talking about, check out Gavin Rothery's blog (VFX supervisor of MOON): http://www.gavinrothery.com/my-blog/2012/6/11/so-what-was-wrong-with-prometheus.html

That is a really good critique. I hadn't noticed the "almost everybody is speaking in another voice/accent than their own" thing. I personally believe that actors do their best acting in their own accents; some actors seem to be concentrating more on getting the accent right than getting across the best performance.