It's almost as if the director woke up one morning and said, "let's strap a go-pro to a guy, give him lots of guns and ammo and bad guys and tell him he's in a real life fps and see what he does". Probably the best action movie I've watched in a long time. The end of the movie gives it that feel that it's not finished telling a story, as is with most FPS games. Always leave it kind of open, if there's enough interest, to carry on. Also get the idea the team who put this movie together didn't really care as much about critics as they did about this idea they came up with.