^Kinda what Doomkid said. I didn't think it looked terrible, exactly, but based on the trailers alone it didn't look great. I enjoy futuristic themes and science fiction a lot, though, so when the reviews came in generally positive, I went to see it.
I liked it a lot, and didn't find the end confusing at all. It was a little open-ended, sure, but I like endings like that - where you can arrive at the implied conclusions yourself. A film isn't necessarily bad if it doesn't spell out every detail with clarity. I'm capable of getting there on my own, and that's all I need, I guess.
I enjoyed the sense of brooding that was accomplished within such a small location, spacially and aesthetically. The earthen or nature-inspired walls were great, like a man-made slot canyon set into a mountainside. The power bumps, lockdowns, and lack of windows in our lead character's sleeping quarters really contributed to the claustrophobia for me. Overall, good things.