I liked the first 2/3rd's of it. It certainly felt like they ripped it straight out of Silent Hill and stayed true to the games (unlike um, Resident Evil lol).
Like many others here, I felt Sean Bean's character was very redundant, and didn't really add much to the movie at all ("OMG there are no men in this movie!?"). I guess they missed the cultists and the cop (unless he was added in afterwards as well).
Once the movie got to the cultist part, it did kind of fall apart for me. One thing I liked about Silent Hill was that you were alone, or at best with 2 other "real" people (while everyone else was either dead in the background or a monster). I didn't mind that they didn't stick with the game's plot, but just seeing all those people there (I have to admit they did look kind of creepy) kind of killed the scariness of the movie for me (and I knew they were going to be cannon fodder for more bloodshed). Yeah, I kind of expected it since I remember seeing a trailer before the movie where a bunch of people ran by the main characters, but I thought maybe they were ghosts or something.
Ah well, it was pretty good overall. Least Rose isn't a secret agent assassin that can kick anything's ass that comes in contact with her, even without weapons (and even Cybil isn't that powerful, which is another nice thing). I'm sure most of you guys know what I'm referencing to (*Cough* Resident Evil *Cough*). Overall I would give it an 8 out of 10 (dropping the 2 points cause again, the movie falls apart at the end, esp. the "congratulations!" part. I LOL'd when I heard that for some reason, as if she was playing a sort of game or something).
Jam it back in, in the dark.