For me, this was a classic case of a high concept idea that cheaps out on actually giving some kind of answer...simply going with the mystical ‘we’ll leave it to you to decide’, it would’ve been nice for the film to actually offer you something.
I’m not the kind’ve person who wants the end of films spelt out for me, but I didn’t feel the writer even knew what the ending was here. In contrast, the dialog throughout the rest of the film is overtly simplistic and busy spelling out the current situations they’re in.
Other than that, it’s the classic set up: a group of different personalities head into an unknown situation where their weaknesses are revealed, you’ve seen a thousand times before.
Watch Under The Skin instead. High concept sci-fi/horror done to perfection.