First off: I have a weakness for bad movies, especially for the ones that are so bad they're funny again... also I like horror movies.
Liking bad movies and having seen tons of them, I can say with certainty: This is not the worst movie ever, not by a long shot.
The story is based on an idea that hasn't been beaten to death already, which is good. Other than that, it's not great, but it works, if you're kind enough to look the other way every now and then, and I actually found it interesting to watch. It's pretty coherent overall, too.
Sure, the actors won't get any awards for this movie, but they do a bearable job. Some of the minor roles are noticeably worse than the leads, but overall the acting is good enough to not be distracting.
The production values are those of a typical non-Hollywood B-movie: Picture quality is somewhere at the lower end, although I've seen worse, the special effects won't wow anybody and the action scenes are pretty weak overall, which hampers the finale especially.
Still, the movie surprised me in a good way. Although it's not bad enough to be funny, it's not bad enough to be a pain to watch, either. I had entertaining 80 minutes with it. Don't expect an award-winning masterpiece, get over the low production values and you should be able to enjoy it, too.