Silent Hill brakes the traditional means of how games are and could be experienced for the action & adventure genre.
It is only after playing for awhile, that you start to realize the town and the game-play, is different from what you have experienced then ever before (Assuming this is your first attempt at the series.). From the dynamic camera angles, disturbing creatures, dark and morbid environments, to the eerie audio effects, Silent Hill easily becomes apparent to be innovative to the horror themed, action & adventure genre and other games of style in comparison; especially Resident Evil.
The game constantly throws the player in different realms of reality, which persistently tests your perception of reality. Silent Hill, despite the general "Survival Horror" genre it is associated with, turns out to be more of a psychological horror that players have yet to fully experience.
The demented adventure, though has not been a best seller to other blockbuster, playstation titles, due to the abstract game-play and story, but defiantly has found it's niche audience; since then, it has become a cult classic amongst horror games and fans alike. Silent Hill has pushed the narrative boundaries of video-game stories and has become a game that fans could enjoy, but not completely understand or grasp it's concepts.
In the end, the original entry of the series, showed that games could be more then just mindless entertainment; it could be metaphorical, philosophical, and to whom who would play, deliver a deeper and more thought provoking experience.
-Mj