Slashers would probably do well as a theater play, though the audience would probably have been hard to find. But we'll get back to this in the end of this review.
First let me say that it was interesting to watch a movie filmed with only one camera, and from what I was told they didn't do any retakes at all. One take per shot, to create that feeling of live tv. The trouble with single take scenes is of course that any mistakes from the actors (or any other mistake) becomes even worse, and the acting here is on a low level from the start.
The story is weak and very predictable, and the characters are pretty lame, making the actors look even worse. The twist at the end (that seems to be a rule for horror movies) is very unnecessary in my eyes, I won't give it away but I'll just say that the story would have been better without it.
But what really made me feel less for the movie was that you really had to use your imagination to see more than what was shown. That's what I mean when I say it would have been better off as a play. In a play you are used to imagining that the scenery is just there to give you a general idea of how the scene looks, but in a movie I want the scenery to be complete. For instance, why did the characters say they where trapped in a room when the walls where only pieces of cloth hanging down from the ceiling, or maybe a paper-thin wall? Why did the characters stand a couple of inches in front of the bad guys without doing anything like trying to hit them or something, and why did they just watch when one of the characters where killed right in front of them? Sure, you could imagine that the walls where really made of concrete (or whatever), and you could imagine that if one of them would have tried something they would have been killed, but this was not what was shown in the movie, you had to imagine it for yourself.
I can't really see what kind of movie audience that would really like Slashers. The horror fans will be disappointed by the lack of story, the splatter fans will be disappointed by the cheesy gore and effects (or lack of them), and the fans of japanese style ultra-violence are way better of with a film like Battle Royale or something. But if you're just out to see a different, easy-to-watch and violently funny movie, Slashers could be worth the 2 hours. But not more.
My vote is 5/10, i.e. barely worth the time.