Many people on my friends list have seen Silent Hill already. Some, like moriarty6, have used their encyclopedic knowledge of the games mythology to help explain some of the more esoteric of it's problems. It's a valid, if doomed for failure, enterprise.

It is a good horror movie, definately a mood piece, and I would urge anyone who likes the games, or indeed good horror (ie - not just jump+scare horror), or hell.. just really well done visuals... to go see it. My thoughts were best expressed however by Tycho from Penny Arcade:

"Silent Hill: The Movie evokes the games without accurately expressing them - to the extent that the movie succeeds at all, it is because director Christophe Gans has mastered the series' visual lexicon. It was weighed down by a faulty script, a terrible kind of smudge across the sheet, but brilliantly directed. It is in this way that it most closely mirrors electronic gaming in a general sense, though (ironically) not Silent Hill, in that it is the sterling execution of a poor narrative."

Anything more is too much, anything less doesn't quite do it justice.