Most games that I find scary lost their luster as time goes on but the ones that scared the shit out of me when I first played them are:
The first two Penumbras. Took me completely by surprise, didn't expect them to be that scary at all.
Amnesia.
Silent Hill 1 when it was first released. Played the intro (where you "killed" by those little things) and had to turn it off.
EDIT: Bonus round. Anyone remember the whacky SNES / Sega game Zombies ate my neighbours? It's filled with humor but I still found it pretty scary, playing it when I was a kid. It was kinda relentless in difficulty so that probably added to it. The chainsaw dudes stressed me out so bad.
The first two Penumbras. Took me completely by surprise, didn't expect them to be that scary at all.
Amnesia.
Silent Hill 1 when it was first released. Played the intro (where you "killed" by those little things) and had to turn it off.
EDIT: Bonus round. Anyone remember the whacky SNES / Sega game Zombies ate my neighbours? It's filled with humor but I still found it pretty scary, playing it when I was a kid. It was kinda relentless in difficulty so that probably added to it. The chainsaw dudes stressed me out so bad.