Didn't deliver what was promised.
Where is the gore and violence? Where is the shocking, brutal and offensive that Rob was talking about all this time? I don't mind the bad acting and poor cinematography but I was expecting some descent amount of violence and practical effects. Horror movies with far more less budget have much more blood, prosthetics and creative ways to shoot horribly violent scenes. It just needs imagination and love about what you're doing and this movie looks to me like Rob didn't gave a single *beep* and just wanted to get over with. I'm not saying this is what happened, but what it looked like.
I saw 'Green Room' the other day which is not a horror film, and it had two scenes that where more bloody and shocking than the whole '31' and that is really dissapointing when your last name is 'zombie'.