Nothing scary at all. It's disturbing though, just like BioShock.
You'll figure out it's a bit like Doom 3 with "aliens" coming out of obvious areas, and after a while you'll have seen them all... The game is still great, you'll have a blast!
Random game thought :
Why is Bionic Commando Rearmed 2 getting so much hate? We finally get a real game and they're not even satisfied... I'm starting to hate the gaming community so f****** much...