I somehow find Minecraft creepier than for example L4D (not saying L4D is extremely creepy) because of those sounds you keep hearing while underground which you will never find out who/what made the sound, and also because of the countless times creepers sneak up on you from behind and blow your shit up

the moment when you hear a creeper and realize your fucked

Dude, I got lost after going off the beaten trail and ended up in a military compound. The military guys were kicking my ass before I found a sewer to lose them in. BIGGEST REGRET EVER. I was chillin' down there, looking for anything to keep me alive and this black monster jumps out of thin air and starts wailing on me. Luckily I had my ak-47 and just blew him away but it still wrecked me. Limping on down I was trying to gtfo because I didn't want to face another. Behind me I hear some wail that chilled my bones, and I get pulled by like an unknown force and I see the face of my attacker (mutated as fuck and looked like it had 4 eyes) and threw me against the wall killing me. Never played again...

I know exactly where you went and what attacked you, the thing that jumped at you was a snork and the thing with 4 eyes was a bloodsucker.

Halo, the first one. The very last Level. The gloomyness or it, seemed so morbid and horrifying to me. It always scared me shitless to play it, that's why I've never beat the last level of Halo. Also the first level where the Flood appear, that was also scary.

Fallout 3

..hl2 zombie town level?