Fallout/Nightmare Fuel

Burned out ruins of proud cities from a long gone age? Bloodthirsty, giant, deformed creatures that once were ordinary humans and animals? Old empty vaults with fading signs of the madness that once tore them up from the inside? Oh yes, the Wasteland is indeed a scary place.

Not pictured: Creepy voices, Vault Dweller's brown underwear.

The Master's Lair in Fallout was quite creepy at the time, as you recognize a Vault...but as you go deeper more and more of the Vault seems directly connected to some kind of biomass...
Many of the death animations in the original games are absolutely horrific. Especially the Lieutenant, who seems to MELT from the inside out as he twitches around.
- Or Frank Horrigan, who manages to rattle out his Famous Last Words despite his legs and torso being explosively separated not half a minute earlier.
Remember those iguana treats, the ones that always provided you with a little extra health? And then going in to see good ol' doctor Morbid, and accidentally going into his basement to discover iguana-on-a-stick is people!!?
The newer games have done away with it, but the first two let you target children. You could blow them up, disintegrate them, put out both their eyes, set them on fire, and leave them a limping, bleeding mess with a single remaining hit point. Or you could just shoot them with a gun.
Frank Horrigan. To call him a monster would be an insult to some of the wasteland's more friendly inhabitants. Its telling that he is the only boss in the series who can't be talked down... you have to fight and kill him. Of course, this is probably for the best.
In the Fallout Universe, Richard Nixon was such a loved president that many items praising him can still be found after the war. Makes you wonder what their equivalent to Nixon was..

Looks like you're out of AP. Time to break out the minigun and hold the trigger down.