This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Silent Hill: Downpour
"Did you enjoy the ride, Murphy?"
"Did you enjoy the ride, Murphy?"
Monocle Man's face in general.
Anytime the Void manages to get a pretty good grip on Murphy. Time slows down, matter and reality itself warp, and Murphy's painful horrified screams echo through the distortions.
Actually, the Void in general. It's a sentient black hole chasing after you! Even when you know the paths, it's impossible to avoid contact with it. And the only reason you actually get away from it? Because the town is letting you get away.
Say you're walking along normally through a creepy environment, only thinking of how to solve the next puzzle...then suddenly, a Weeping Bat drops right in front of you, from the ceiling.
The Weeping Bats are plenty creepy on their own by virtue of being in earshot, but not always in sight. You can hear their gurgling growls and even their scurrying on ceilings, but good luck trying to see them until they decide to make themselves visible, and when they do, it almost always causes damage.
The stone-still miners. Early on, you find three of them behind a fence, just staring at nothing. It's creepy enough on its own, but if you get too close, one falls over for NO reason.
Look closer at the miner that fell. It didn't fall over like a statue that was pushed... it fell like a human who'd been shot. Statues don't change positions for any reason... what if these 'things' are alive all along?
Then the train part itself: During the ride, you stop right by an 'exhibit' of miners, all standing in various positions. Suddenly the lights go off...then when they come back up in a brief flash, the miners aren't in the same positions they were before. And they moved closer to YOU. The lighting repeats this off and brief flash pattern, and each time, the miners keep getting closer, until they're inside the train itself. Then the lights go back on permanently, and they're right back where they were at the start. Unnerving doesn't begin to cover that.
One rather creepy moment when Murphy reaches Devil's Pit and is about to go down to the train in the caverns. You can put money in one of those binocular things. Look up at the train car, and suddenly a bloody hand reaches up and slaps the window before sliding down it. What makes this even worse is that there's no explanation for it, and there's no cutscene in the tram while Murphy is riding it to give any indication of what happened to randomly put someone or something in there.
Another creepy thing can be seen using the binoculars, specifically the ones on the level below after fighting the pair of Screamers. Looking at the lower deck where JP later commits suicide reveals the Wheelman, who rolls along, stares directly at Murphy for several seconds, and then vanishes.
In addition, viewing the lower deck using the binoculars on the upper level will reveal a hanged corpse that can't be seen any other time. This also acts as Foreshadowing.
The introduction of the Doll enemy. You enter a pitch-black basement, and in the distance, behind a barred door, you hear someone sobbing hysterically. So eventually you get the door open...and the sobbing turns into an evil cackle.
What's worse, in that house, it's dark, but there are still sources of light. The door is barred, and you have to cut the power plunging the house into full darkness. Walk through the door that's now unlocked, and grab a health pack, when suddenly, you're attacked by an invisible, invincible, extremely strong shadow out of nowhere!.
In the Centennial Building, a chilling "Sequestered does not equal safe" shows up on the wall under UV light in the City Manager's room, next to a corpse where you have to get a Director's ID card for extra room access.
If you equip the UV-light you'll see that the room is absolutely littered with the footprints of the invisible creature that's been stalking you since you entered the building. The same creature that dropped an entire walkway on your head not moments before, just for giggles. And now we learn it's capable of murder.
Even worse, every single one spawned is designed to prolong your suffering when escaping the Otherworld. One badly-timed move though, and you could be knocked on your back, directly in front of The Void, and it's impossible to escape in time before you're ripped apart.
The loading screen will occasionally have such gems as "They never really loved you," "you can't ignore it forever, "why are you lying?" and "We're all slowly dying."
Even worse, "They know you’re alone.", followed by "It's in the room with you. You just can't see it...".
And worst of all, "STOP DOING THAT." That one is almost guaranteed to make you jump, no matter what you're doing at the time.
Gets a reprise in the Monastery. This time you get to pull the axe out of the still-warm corpse. Yay. Then at least three Dolls appear out of nowhere as soon as you do...
In the apartment, there's a dead guy hanging from the ceiling fan, and a sidequest entails giving back items he stole from the other tenants and putting them back where they belong, thus appeasing the ghosts. If you leave the apartments and come back, he isn't there anymore. Just his clothes lying on the floor. You can wear those clothes as an alternate outfit.
The X-ray puzzle in the Orphanage. You have to reach into the stomach of an apparently dead Screamer to search for a key. The monster is indeed still alive and very much not pleased about this, in case you were wondering. And for that extra bit of fun you have to manually guide Murphy's hand through its bowels.
The game indulges in a lovely bit of Fridge Horror; in the mirror sidequest you're made to play a game of Spot the Difference, adjusting the room so it matches its counterpart inside of the mirror. Should you get anything wrong, however, a monster only visible in the mirror will spawn. While normally one would just finish such a task and be on your merry way, when you solve this one you'll acquire a therapist's notes on the apartment's former occupant. She had been driven utterly mad by the fact that if she failed to perform the same ritual of rearranging the room every day, "the people in the mirror will cause her physical harm".
An early event in the prison level can pretty much be summed up as "Press this big glowing red button for the mother of all jump scares!"
Probably the jump scares in general: most of them come out of NOWHERE, and are erratically placed throughout the game, screwing with your expectations of when you think they'll appear. And even worse? Some can kill you if you don't react fast enough.
Special mention goes to the giggling unseen assailant in the Centennial building, dropping boxes and entire floors on you.
Not unseen; there are at least two glimpses of her(?) when she(?) runs past Murphy cackling, only to vanish into thin air. This might actually be more disturbing.
The hanged body in the Monastery playground. The worst part is is that it changes from being a corpse to a tire swing whenever Murphy looks away, upping the Paranoia Fuel levels for the unwary players that think they just saw something change. Another hanged body can be found at Devil's Pit, using the binoculars to look below the lower deck. It just seems so out of place, until you realize it's probably hinting at JP's suicide on that very level.
The deeply unsettling music that plays in the playground area does not help.
You can run into a glitch where the corpse stays there. Blankly staring into oblivion. Forever.
The Hillside Apartments. One of the darkest, creepiest, most ambient areas in the entire game. Ironically, there are no enemies there.
A few of the sidequests, mostly due to the sheer random levels of Body Horror and general Nightmare Fuel. Some gems include reuniting a man with his still-beating heart that has been ripped out of his chest that is found in a sewer, and summons hordes of howling monsters to pursue you through the maze-like area after it is picked up; attempting to put the spirits of a dead woman and her children to rest while avoiding the axe-wielding, enraged spirit of the husband, who murdered his family; entering a creepy, abandoned movie theater; and entering three horror films, which correspond to the events of Charlie's kidnapping, molestation and murder.
The telltale beating heart sidequest. It's bad enough that you're in a sewer level looking for a human heart, but the fact that you have to listen to the SPEED and VOLUME of the heartbeat to figure out where it is, and the moment that you pick up the heart all hell breaks loose.
The room with the murderous husband's ghost is worth elaborating on, simply due to the way you discover what happened. You have to reassemble the gramaphone and play a record on it, causing you to see a corpse appear in the room. Murphy mutters about turning back time, at which point you must play the record backwards, causing you to see the husband coming down the stairs in reverse, occasionally distorted as if he's twitching violently. The whole murder of the wife plays out in front of you backwards, and once it's over, his spirit comes out of the painting on the wall to attack.
Shortly after leaving Devil's Pit and before moving towards Silent Hill, the large covered walkway Murphy is on is shake violently as something large and monstrous moves around the area, making grotesque animal sounds. Nowhere in the game is anything fitting this description ever fought.
The first official introduction of the Bogeyman. Despite having a silly name and resembling the offspring of Nemesis and HUNK, he lifts a young boy into the air, and, as he gasps for breath, snaps the child's neck in front of Murphy. The fact that he is implied to be a memory of Murphy's son Charlie doesn't help. Infant Immortality? What's that?
The Wheelman, full stop. While his appearance in the final boss fight can be underwhelming, his earlier appearances from afar definitely give him an aura of mystery and fear. He is first seen watching Murphy from a window of the Devil's Pitstop motel when he is talking to Blackwood, can be seen briefly at Devil's Pit using the binoculars, is seen moving through a newly unlocked gate on time-lapsed, grainy security camera footage in the Centennial Building parking lot, is seen watching Murphy as he rides in a cage/elevator in the Centennial Building Otherworld and finally, watches Murphy through the bars of his cells as he awakens in the Overlook Penitentiary building.
Gets worse if you search everywhere with the UV flashlight: in some places, there are wheelchair skid-marks. Meaning he's always one step ahead of you, no matter what you do...
Thanks to the more advanced graphics, the Otherworld transtitions may count now. In previous games, you either were suddenly in the Otherworld after a pitch-black shift, or you see the area around you rust/blood over, but either way, you never saw much of the shift from 'normal' world to Alien Geometry type... but here, you see the world around you outright dissolve or outright melt away, like it never existed.
And who knows? Maybe the foggy town you wander into is just a fake... Silent Hill already twists its monsters to each individual, why not the entire town as well?
The 'Ribbons' sidequest, that one was messed up.
To elaborate, you find a missing poster of an 8-year old girl who disappeared while walking home from school. The girl was autistic so in order to help guide her through town, her mother placed several ribbons of three different colors to tell her which way to go and which way to not go. So Murphy follows these ribbons around time according to how the girl would have followed them, only for the trail to end at the pier with only a key on the ground and no little girl in sight. The key is for an apartment, and if Murphy were to go there he'll find a note written by the mother. It turns out that she was fed up with her life and unwilling to continue taking care of her autistic daughter, so she purposely placed the ribbons around town so her daughter would follow it to the pier and then drown when she fell over. Also could count as a Tear Jerker.
The Diner has an odd sound repeating every once and a while. It's part of the soundtrack, but doesn't show up anywhere else, and sounds like something is there with you, but nothing is. Also, if you wander around the basement, soon, it'll sound like something just closed the door, and the camera even focuses on it, but you know what? It was nothing.
The Centennial Building parking garage has a part where Murphy must drain a room of water. He goes down there and finds a security guard, brutally murdered with a wheelchair next to him. You grab his ID Card, and suddenly, the room starts to fill back up with water. Murphy makes it out and finds the entire garage has become positively filled with Weeping Bats, who have murdered a police dog and have torn everything up. They appeared in the span of 30 seconds at least, and no explanation is given for why the water filled back up, or where the Bats came from.
When Murphy uses the ID card to open the elevator, you can see The Wheelman on the security monitor, wheeling away. At one point, it looks like he glances up at the camera for a bit. He knows.
The third floor of the Centennial Building first has Murphy balancing on some precariously-placed beams stretching over missing sections of floor, while that cackling, semi-invisible creature that's been stalking him runs around beneath. Also, multiple Dolls can be heard laughing and moaning somewhere nearby (in fact, they ambush Murphy as soon as he dismounts the last balance beam and the floor is infested with them).
Deciding to examine the vehicles in the Centennial Building garage rewards the player with some glorious jump scares. Examining the back seat of the police car results in a police dog leaping up at the windows and barking. The worst one, however, happens if you examine the back of the van (which, upon approaching, causes the walkie-talkie to emit static). Murphy slowly opens the doors... and finds nothing but bloodstains. After a long, deathly silence, a Screamer suddenly launches itself out of the shadows and latches onto his back.
Added Paranoia Fuel when you realise it's the same creepy white van that's in the background of every silent hill game. That Van that blocks Heather in the mall back alley in Silent Hill 3? Same. Freaking. Van.
The prelude to the Post-Final Boss. Anne had been showing signs of instability all throughout the game, but here its made clear she has well and truly snapped.
It gets worse; at first it's just Murphy facing Anne, trying to reason with her. The camera turns on her as she rants, making it clear exactly how she thinks of him, then it turns back to the angle focusing on Murphy... except we see The Bogeyman, speaking in Murphy's voice. Just when you wonder what the fuck happened, it slowly dawns on you; this creature didn't suddenly show up and shove Murphy out of the way while you weren't looking, or killed him; in Anne's eyes, he IS the Bogeyman. But not just appearance-wise, oh no - the next playable sequence shows that the town literally TURNED MURPHY INTO THE BOGEYMAN, complete with instinctive rampaging on Anne.
While the "Execution" ending can seem quite disconnected from the overall narrative, it still has some very potent nightmare fuel in the form of... Murphy himself, who's revealed to be a complete psychopath who murdered not only Frank Coleridge, but also his own son Charlie, purely to spite his wife and prevent her from getting custody. He shows no trace of either remorse for his actions or fear regarding his impending execution, and only speaks to toss out some defiant last words towards Sewell. In a game full of monsters, both human and otherwise, the protagonist can be revealed as the most cold-blooded and evil of them all.
The Monastery has a pretty chilling series of letters/journal entries you can find laying around following the time one boy spends there. It turns out his parents admitted him, and his physician either doesn't seem aware of or just doesn't care that the boy is obviously autistic (as the symptoms described in her notes and letters make perfectly clear) - he writes to his parents at one point, begging them to let him come home because the people there are mean and the medicine they give him hurts his stomach (and can be heard crying at one point), and one of the staff posts a notice that any and all incoming or outgoing correspondence to and from the boy is to be brought to her first for review, with no exceptions. The physician subjects the boy to various harmful medicines and treatments in an effort to "cure" him (including electroshock therapy), ultimately deciding that the treatments can do nothing to help him, and schedules to have the boy lobotomized. One of the letters you can find has her subsequently writing the parents to inform them that their son died during "routine" surgery, and a reminder to them that they authorized these procedures when they brought him in.