Silent Hill is a sleepy little tourist town somewhere in Maine. It's somewhere between "large town" and "small city" in size, sprawled out across Toluca Lake.
The area is inhabited by a kind of spiritual/demonic force that "channels" itself through the minds and emotions of people. It tends to go for Deep Seated Issues, phobias, and fun stuff like that, changing the surrounding area to reflect them. While there is currently a main channel for this, y'all can feel free to tweak things to give your pups maximum freakout potential. The whole setup is, literally, a nightmare made real.
Foggy Silent Hill is the regular mode that most people will first experience. The town is empty of people, full of fog, and crawling with monsters. There are occasional roadblocks, usually in the form of GIANT DAMN CHASMS RIGHT IN THE ROAD, but also from things like collapsed overpasses. It's snowing outside.
Dark Silent Hill is the second mode, brought on apparently randomly. The area around a person darkens, accompanied by the sound of sirens. The place looks a lot like the art director for an industrial music video was let loose in the place with an unlimited budget: most of the surrounding floors and walls are made of chainlink, metal grids, and barbed wire; there's rust, blood, and unpleasantly organic-looking things all over, and there are more monsters. Oh, and the occasional corpse, and weird-looking figures in robes displayed in gibbets. There are also strange symbols (see the icon in this post) burned into various places. Outside, it's raining.
The two landscapes occasionally have differences in layout.
Electronics- Tend not to work. Cars cease to function (and the roads are mostly blocked, anyway), radios and televisions just play dead air, telephones just won't work. However, radios and cell phones will play static if there are monsters around, and sometimes broadcast equipment will get "hijacked." Some areas have functioning city lights (though never in Dark Silent Hill). It's impossible to contact the outside world while inside.
Underground Tunnels- Radios and cell phones will not play static around monsters in here. They are the scariest damn place ever.
Powers- May or may not work, or may function at reduced capacity. Since the city is now a nightmare, there's definitely a sense of helplessness. Dream logic.
Doors- Most of the doors are jammed and can't be opened. It's a thing. You'll get lucky every once in a while.
There's a big big list on Wikipedia that includes places that are non-plot-centric, if anyone wants to go gallivanting around elsewhere. Also, this is a pretty good expanded list of areas in the town.
Areas around town:
Old Silent Hill: Chiefly residential areas with a small bit of commerce. Connects via bridge to Central Silent Hill.
Central Silent Hill: [More of Central Silent Hill] The business district. Has a mini mall in the form of Silent Hill Town Center, as well as enough quaint little shops to keep any souvenir-minded tourist happy.
South Park: The resort area, full of hotels, motels, campgrounds, and various shopping attractions. There are docks by the lake, and access to Lakeside Amusement Park and the Lakeside Hotel. There is also a secret drugrunning business going on in some of the stores.
Important locations for the plot include:
Midwich Elementary School, found in the southwest part of Old Silent Hill. There's a clocktower and an entrance to the water works tunnels here. It looks to be a religious school.
Balkan Church, at the intersection of Bloch and Bachman in Old Silent Hill. It's a medium-sized church, fairly old-fashioned.
Alchemilla Hospital, at the intersection of Crichton and Koontz in Central Silent Hill. It's been refurbished in the past decade, but still clearly an old building.
Green Lion Antique Shop, located in the northeast area of Central Silent Hill. It's a tiny hole-in-the-wall place.
Lakeside Amusement Park, west of South Park on Sandford. A nice little park with various rides, including a carousel, rollercoaster, and a haunted mansion.
Pterodactyl thing- Humansized flying bastards that wander around outside in Foggy Silent Hill. They tend to swoop in to either rake with claws or bite, then flap off before you can hit them. Make horrid screeching noises, and their wingbeats are audible from a distance, though it's hard to tell where they're coming from. Fairly weak, overall.
Skinless dogs- Big damn dogs (shoulders about the height of a man's hips) with no skin. They live on the streets of Foggy Silent Hill. They growl, wander around, and attack people. Annoying, and tend to be in groups, but can be somewhat easily beaten down.
Horrible faceless children- These guys live in the school. They make a horrible noise that sounds like the bastard child of laughter and groans of agony, and they carry knives, which they want to stick into you a lot. Can be alone or in groups, and will often gang up on a person, with one or two latching onto the knees while another makes with the stabbing. Fortunately, they're pretty fragile.
Ghost babies- Another schoolkid. Little shadowy toddlers that squeak and run around and occasionally fall down. They can't actually be hurt or hurt anyone, though they still make the radio go off. They're cute until you realize that you were paying attention to them while one of the horrible knifechildren was creeping up behind you.
Apelike dudes- These adult-sized guys live on the streets in Central Silent Hill and South Park, both in the Foggy and the Dark modes. They have low, grunting voices, and like to tackle victims and try to bite chunks from them. Pretty tough, but slow enough to dodge, provided you see them coming.
Nurses- They live in the hospital, along with similarly-affected doctors. They groan and try to stab intruders with scalpels. Another ganging-up type- one will try to grapple while another stabs. They're about average human toughness. The quivering fleshtumor thing is a weak spot.
Pterodactyl thing + worms- These are the Dark version of the regular pterodactyl things. They're tougher, stronger, and have worms on their heads.
Skinless dog + worms- Like the last one, only with the dogs this time.
Giant roaches- Nuff said. They're about a foot long, and found pretty much everywhere. One well-placed stomp will do them in, though.
Huge praying mantis bastards- Live in the sewers. Come up to a man's hips. They like to crawl around in the pipes and JUMP DOWN ON YOUR HEAD. They'll also just walk up to you an try to slice you open with their claws. Their exoskeleton is pretty tough, so they take a while to die.
Awful sneaky bastard monster- Another sewer dweller. They're about child-sized, but have MONSTROUS CLAWS which they like to stick inside you. They also make NO NOISE WHATSOEVER. Otherwise, they act like the child monsters. They're about middling tough-and-strong.
Tumor things- don't tend to show up a lot, but they do exist. They're grublike creatures that burrow into a person's back and take them over. (This is what happened to the doctors and nurses.) It's possible to "evict" them. Ask me for details if you're interested.