Oh, man. FEAR's single player is awesome. There are some minor AI issues, but not that distracting from the game. (Example. the ATC clones sometimes try to hide behind handrails.)
Its sooo creepy. I play Quake4, and stuff, but Strogg are nothing compared to Alma.
Its not "monsters jumping out of closets" scary. Its just overall "makes your skin crawl" creepy.
Craig Hubbard summed it up best: "a guy in a mask chasing co-eds with a meat cleaver can be scary, but on some level you're thinking to yourself you could probably kick his ass if you got the drop on him ... but when a spooky little girl takes out an entire Delta Force squad, how are you supposed to deal with that?"
I have yet to get Extraction Point, but its supposed to be even better.