SCP: Containment Breach can be extremely stuff-your-pants at times, Amnesia also can, but in a different way.
Containment Breach gives you the constant fear that there's going to be an SCP standing right behind the corner in a dark corridor, and Amnesia has its creepy ass atmosphere. It always keeps you on edge, and when you finally see the monster, then you get the living stuff scared out of you. while it chases you through a corridor, the disturbing music playing all the while