It looked great, Brad Pitt was excellent. Worrying about whether the science is bang on is not worth it in a film that is not about the science.
But the filmmakers caught themselves between two stools. They wanted us to wonder but then had everything explained by Brad's thoughts as we went along in case we wondered too much, so there was no wonder in it. It wanted to come across as contemplative but then couldn't resist some pointless 'action' scenes (moon battle, crazed monkey) because someone was afraid we might have got bored with too much contemplation. Trying to reach all perceived audiences so overtly left me quite bored quite quickly. (There was a warning of this tendancy right off the bat when, having picked a high brow title, they couldn't help themselves from translating it in the opening seconds. It didn't matter! We didn't need to know!)