I'm torn on this. For what is essentially a yurified Roland Emmerich disaster movie, the induced anxiety is superb and forms a great backdrop of looming dread for exploring the girl's psyche. That works really, really well. But then there's those interludes of humanity banding together. They are probably meant to be inspiring, but honestly come off as rather comedic. (I mean, us being bumbling idiots is painfully realistic.) With all suspension of disbelief spent on the slow-falling rock, I can't bear the second attempt... Then there's the "I want to kill everyone yet end on a (bitter)sweet note"-ending which feels contrived and adds to the mood backlash.
I think this gets better with time, when you start to forget the weird parts.