Oh dear...I was really looking forward to liking this, and I agree a lot of it has some cool stuff and original ideas but for me, it lets itself down in so many areas:
Characters; I don't know about Bob, but I just couldn't get attached to any of the characters - especially the main guy, this was a film that concentrated on premise and forsook character building. You learn about 3 things about each character and are expected to care about them, and they're introduced one after the other and then they disappear for half of it.
Writing; cliche after cliche, I'm just tired of it now - you can't watch this after watching the social network, it makes the gap more apparent. The script is trying to be badass and macho, but it just leaves the actors with no room to emote or act like real people! Bob's always going on about how likable characters make exciting action sequences (I wholeheartedly agree), but this just doesn't manage it.
Rushed: Other than the brilliant first 10 minutes where there's no dialogue, every other scene is rushed and leaves little opportunity to invest - Bob says it 'blows through it', but that I'SNT a good thing! Also there's a good scene with the cannibal vampires in a house that could've been made sooooooo good if the director had just taken their time to build tension - but it's just in, out.
Wasted potential: there were some bits I loved in this film - the beginning, the return to the human stock and the cannibal vampires, but it was just all wasted and not brought out it's full potential. If the film concentrated on the cannibal vampires a bit more and gave more time to the characters and writing, this film could have been AMAZING, but as it stands it barely registers as average.