For a movie that is just making it up as it goes along (corner points were given to the actors, as in beginning of the scene and end of the scene, do as you please in between), this is not half bad. Even if you didn't know that, you will realize that the actors are making stuff up as they go (coherent and continuity be damned).
Which is a shame because things are there that could've been explored more and just looking good (especially the female lead), is not enough to keep you hooked for a long time. So our comic relief does a good job and he has quite a lot of jokes that almost make this a way better movie than it actually is. Unfortunately that thing, about this not making sense, characters behaving, like they are in a mental institution, where they lost their brain and other things like that, will kind of take the fun out of it ... literally.
All this is based on a true story. Yes really! Actually the two guys (no girl in that story, at least not one that was alive) who owned the real mirror of the story were at a screening at Frightfest and told us a few stories. You can either believe those guys or not. They sold the mirror on ebay to someone in Germany and the director found out about this and thought: Hey why don't I make a movie about this? Well guess what? He did! I know! Shocking. Almost more so than the movie itself! Which again, is only really "saved" (not literally), by the jokes of one of the characters ..