This game really gets to me. I have to stop playing every few quests simply because it's pretty unnerving.
Mostly cause I'm playing at night with headphones on and those guys just... don't... stop... screaming...
Also, random creepy music and sound effects playing for no reason whatsoever. I dunno if it's a bug or what but it's really, really unnerving to be exploring an underground toilet and SUDDENLY CREEPY MUSIC AND CRAZY WOOD SPLINTERING AND SCREAMING. It's like "WTF WHERE ARE THERE DOORS HERE?! WHY IS THIS MUSIC PLAYING?! DIDN'T I KILL ALL THE ZOMBIES HERE OH GOD". And I run around looking for where the hell the noise is coming from and it's just a random sound effect.
Seriously... that's really hard on the heart.
I noticed one of the soundtracks has the god damn Sprinter's scream meshed into it. They really know how to screw with your head.
Oh, and by Sprinter I mean Infected. I kinda use "The Zombie Hunters" designations for dudes, and it fits pretty well, except with the Suicider, which I gave the Mercy name to. Not because they kill you quickly, but because the first time I saw one
it begged me to help it. The manual says they're still somewhat aware or and whatnot, but I didn't expect it to be creepily creepy.