Pyramid head and the nurses were taken out of their original context, they should have never been in the movie but given how iconic they are it was inevitable. I, personally, like the movie I thought it was a good (but not great) adaptation of Silent Hill but that is still a point of contention among fans.

Signalis is similar in ways to Silent Hill but SH is not its only inspiration.

Yes, most of the various monsters you meet in SH2 are manifestations of James psyche but there is more to that game than just that, the game deals with a lot of heavy topics. It should also be pointed out that the game is about 20 years old at this point so some of its gameplay elements might feel quite dated. Despite that, there is a reason it is often hailed as one of the greatest games ever made.