|That's the last time I'll accept a blind date in Silent Hill.|
Just take a moment to look at your side quest to see if it isn't something out of a more action-packed arcade-style game or dungeon crawl. There shouldn't be a series of monsters that you need to fell to pick up a first aid kit nor should there be a series of rooms that each have their own monster inside. Focus on terrifying revelations, simple but interesting puzzles, and the occasional shock. Some of these side quests might not have any monsters or other confrontations and instead simply provide more clues as to the world they have found themselves in.
Lastly, as always, think deeply into your player characters when designing monsters, developing NPCs, and thinking up puzzles. Do they really need an icon of rape and masculine dominance such as Pyramid Head to enter their world? If not, don't include it. The NPCs should highlight an aspect of the character as their worlds wouldn't collide and they would never meet if there was nothing that called to the other. A player character who committed industrial espionage might come across a suicidal individual who eventually kills themselves over guilt toward their accidental actions towards a trusted loved one. A player character who ignored their depressed wife until she slumped into an asylum might meet a manic depressive who is desperate for love and attention. Someone with anger management issues might just come across a person who pushes their buttons.
Silent Hill is a crucible. It doesn't lead you gently to atonement. It might not even want you to atone. It just wants to give you a shot at it. It will bloody you, bruise you, put you through the wringer, and maybe, just maybe, you'll have enough in you to crawl out of that hell hole and back into the real world. You won't be stronger when you get out. You may even be broken inside. But you will be wiser.
Silent Hill bears more of a resemblance to Jigsaw's rationale in Saw rather than a vengeful angel. It tests you. Maybe you walk out of there. Maybe you don't. Maybe you deserve it. Maybe not. Sometimes you aren't even the protagonist. You're just someone else's test.
Bear all that in mind and you should have one epic Silent Hill game.
A campaign based around Silent Hill: Downpour, or including elements of it, should appeal to Explorers as there is a story in pretty much every place you enter and its fascinating to simply see how a person's psychology and the sins of the past will be reflected in the world around them. Investigators will be similarly fascinated by these stories and will make a point in trying to figure out the various details of it. They may want to pause in further explorations just to make sure that they've tried every door and learned all they could about a situation that might have led to this particular moment.
Communicators will probably get a kick out of seeing their character's psychology through the eyes of Silent Hill as well as seeing how their characters will react to each crucible. As they're most motivated by exploring their own character's psychology, and to a lesser extent, the psychology of those around them, expect a very realistic series of encounters. They may decide to hole up someplace. They may fall apart quickly. This is fine. So long as they're having fun this shouldn't be an issue. You can always find a way to motivate people to leave in surreal horror or even let them fall to the threat if that is likely. They can then pick up another character and explore that one's mind.
Action Heroes will generally want a more hi-octane ride than the foreboding atmosphere but the fact that you need to kill the odd monster in Silent Hill and run away from others should appeal to them. Generally they prefer being kick ass and untouchable but if they're a fan of horror they might enjoy exploring a more vulnerable side to the combat characters they more often play. I have a dedicated Action Hero player who really loves surreal horror because the pacing is fast and fluid, there's always something to see and do, and the game rarely bogs down into finicky issues of consequences and obeying authorities like the Masquerade or hiding from police.
Tacticians will probably like this style of game the least as they innately try to find some sort of goal to work towards and will get frustrated by the meandering path they will need to take to get there. Your best bet is to simply give them a number of rather clear objectives that can arise organically from the gameplay. Rather than the Silent Hill 2 style where you randomly try to open up doors and then you're in an apartment building and you mosey around for a bit and then you're following a little girl out of a hospital and into a nightclub, you should encourage the Downpour style. Murphy wants out so first he needs to get into town via the mines and through his journey he overhears a radio DJ so he goes to meet the DJ who gives him directions to a possible out and so on and so forth. While there is still a bit of a ramble, there are also clear objectives.
It also helps to reinforce to the player that they should try taking their hand off the steering wheel and relax into the flow. If they go toward the hospital, then the hospital was where they were meant to go all along. That way they don't feel stupid trying to plan out where they're meant to go and realise that they just need to do whatever they need to do and deal with what is directly in front of them.