Are Silent Hill games related one another?
Only 1 & 3. 2 and 3 are completely different stories.
SH2 and SH 4 is related to each other actually. You can read a lot of info about Sullivan in SH 2.
SH origin and 1 are also related.
SH4's story has nothing to do with SH2's though. You only hear about Sullivan in SH2 through newspaper articles and letters, but his story has no connection to James Sunderland's at all (in fact, James's father is the janitor in SH4, nothing more). The only reason it's a bummer that they left out The Room from the HD collection is because it's one of the last true SH titles from a good deal of Team Silent, not because it has any relation to SH2. If anyone would know that, it would be me.
As far as Origins and the original go, I didn't say they didn't have any relation. They just aren't needed for the collection.
Whoa, whoa, whoa! Did you just say that James father was just a janitor and nothing more. While he doesn't appear too often in the game, he did play a pretty big part in the whole Sullivan story. He was the one who found Walter when his parents abandoned him AND he, very creepily, kept Walter's umbilical cord.
Anyway, I do agree with you that SH4 does not suck. I'd have to say it comes in a very close 3rd, just behind SH2, as my fave Silent Hill.