A bit short, a bit terryfing, a bit of everything, but the great thing of it is graphics.
Now, graphics...ah...graphics. Only one word: great! The light effects in the game are the better of all: how firing a weapon lights the enviorment and your enemies; how lights move when you shoot at the lamps...it´s simply wonderfull to see it. Anyway, the graphics flacks in textures and originality of places (more textures would be apreciated) but F.E.A.R focused in lights and people and things models, above else.
Sound is good, specially in single-player, more specially on terror scenes. Make sure to have sound on when you paly...or off if it afraids you too much (or makes you waste ammo when you hear something in a empty corredor).
The value of the game (at least in my country) is a bit too high.
Multi-player experience is something normal, there´s not much difference between F.E.A.R and Counter-strike. I mean, in SP you have to cover; in MP you have to run and jump and duck like a demon. Anyway, it got´s something Counter-strike can´t give: slowmo. Nothing really spectacular, but it´s fun to kill others in "matrix mode" and frustrating when other player activates it to kill you.
F.E.A.R is a shooter focused on graphics, remember. So, before playing it, be sure you can play it with at least medium graphic quality or you will miss a lot. In fact, if you play in minimun quality, you won´t notice any difference between F.E.A.R and SWAT 3. (And specially, be sure you can play it on HIGH before giving it a 6 on note in graphics when review...).
Finally, I can say F.E.A.R is stunning graphically and gives you a few 10-15 hours of fun before heading to MP and give a lot more. Have fun with F.E.A.R and...terror.
Sorry if there´s any spell-gramatical-writting error, but my base language is not english.