I found it to be rather bland. It didn't do anything new, though it did the "we've lost communication with X, let's go check - Monster!" trope reasonably well.
I felt it frustrating that the two most interesting parts of the story - how the world got the way it was, and how they were going to survive in this barren place - were not fleshed out at all.
How can they know about the helicopter and the bridge and still find that car on the bridge for the very first time? Why can't the cannibals use guns? What's with that guy Mason, trying to kill his own while the cannibals are attacking?
If you watch this movie entirely, your punishment will be to watch this movie entirely
Ninja. Cannibals. Machete wielding ninja cannibals.