This movie flew completely under my radar, so I had no idea what to expect going in. I found it surprisingly fun and quirky. It plays out like a cross between a caper movie and an old private eye flick, but with enough surreal touches to make you question the reality of what you're shown.
The movie is stylish, I enjoyed the little touches like the constant physics references, and it did a good job of creating a sense of anticipation as it drew me in. Unfortunately I wasn't satisfied with the ending. To try to explain it, the ending is not what you would expect in that it is what you would expect if you weren't expecting more. OK, that probably doesn't sound like it makes much sense, so I'll try to clarify in the spoilers section.
I'm giving it a 7 out of 10. Basically, it's a fun and slightly unusual movie, more-so if you don't have any expectations and just let it take you for a ride.
#####SPOILER WARNING#####Coming back to the end, I thought it was too simplistic. Yes, it explained everything and tied up all the loose ends, but it was just too mundane considering how the movie increasingly flirted with the metaphysical towards the end.
Also, the bit with ground collapsing in a line that chased their car was just silly and, worse, out of place.