It's one of those games that is has a really astounding single player. Those rarely happen these days.
The multiplayer sucks, but then, so did Half life's deathmatch. It is always up to the community to come up with worthwhile mods for this kind of game. I have no idea what kind of modding ability the game has. I have not heard of anything.
Ulma is creepy. The last level or two, when you really realize what is going on, it was creepier and more unsettling then any movie I've seen. When you see her the last few times, it's just plain disturbing. People talk about the horror video game, and no one really believes it could be any good. FEAR got it dead on right. Makes Doom 3 look like it was made by little girls.
Screw multiplayer. It's worth the 40 bucks it would cost you at a best buy. Even if you only play through once, you'll have a good time. Just make sure to play it at night, with the lights off and the sound turned up. It's worth it.
-Local