At first you might think this one is a slight variation on Halloween with a tiny bit of The Excorcist thrown in - that's what I thought too, until I got about halfway through. At that point, it becomes something much more; we get to see some pretty great ideas and a few truly creepy moments (such as a killer with nylons over his face). There are too many interesting visual moments to list, but here are a few: sinks that catch fire; mirrors obscuring their reflected image with fog or black paint; an evil, broken mirror painstakingly reassembled (reminding me of Duchamp's Large Glass); and a slow reverse zoom-out, implying that an unseen entity is watching from above. I think my favorite sequence in the film is when a young kid tracks a shard from the evil mirror onto the bottom of his shoe, then goes fishing and unknowingly reflects sunlight onto a group of teenagers partying at an abandoned house across the lake. This causes all hell to break loose, as the teenagers begin to kill eachother off, as if controlled by the reflected light (a literal Shining!). I'll just say that there are lots of other interesting things that happen with those mirror shards.
The main theme music blends Carpenter's Halloween theme with Mike Oldfield's Tubular Bells, but that isn't nearly as interesting as the incidental synth cues heard throughout the film, as well as the excellent end credit music, which features crazy detuned synths, big pitch bends and organ chords. All of the music is provided by Tim Krog, whose only other film music would be for Boogeyman II, which was released three years later. Interestingly, one of the main characters (Lacey) is also one of the co-writers of the film, and her brother in the film (Willie) happens to be her brother in real life; that might be why there relationship onscreen is so interesting.