What does all the monsters in silent hill games represent?

That's a long list. The wiki link posted here has the best information.

Here's a link to the monsters that appear in the movie:

http://silent-hill.org/silent-hill-videos/the-mons...

Silent Hill Monsters

That's a rather long list. Generally speaking, monsters are manifestations extrapolated from a particularly disturbed psyche (representations of guilt, fear, phobia, etc.). Most of the SH1 monsters are taken from classic demonology, since they come from the mind of a girl sacrificed by a pagan cult. In SH2, most monsters are explicitly feminine and highly sexualized, because of the protagonist's impotence/sexual frustration. The monsters from SH3 have an organic/grotesque motif in tandem with the game's birthing/impregnation theme. In SH4, the ghosts reprent the victims of a serial killer. In SH0 and SHH, it's basically a rehash of the older series monsters, coupled with a few additions that tie to the protagonists' past. And SH Shattered Memories, well, there's only one kind of monster, and don't want to give away the plot.

For a more specific approach, go to: http://silenthill.wikia.com/wiki/Category:Monsters

http://silenthill.wikia.com/wiki/Category:Monsters