I've had this game for a hwile now and would say it's a very good game.
As Syno above said the single player is fairly short, I completed in 9 hours (damn you SynGod!! :p )....but for me the whole point is the Multiplayer mode.
At first glance the amount of levels look few, but when you start playing them there is so much to each map that you realise why. (more official MP maps are being released as well).
There's a three MP modes: complete the objectives, domination-esque & another which swaps the teams over after the time runs out (from what I can remember). There's no deathmatch as such, but that's kind of a relief as it wouldn't work at all. Leave that for your UnReal.
You then have chose of the role you want to play, ie. Medic, Soldier, Leutenient or Engineer. All have there part to play, such as the medic being able to drop medipacks for other players, and also being able to revive non-mamed players. The soldier is normal, chose your weapon kick ass. The Leutenient can drop ammo for players and also call in airstrikes (class!). The engineer can set dynamite to complete objectives and all can fix damage weapons.
All-in-all I think it's a game that will lastability due to it's MP experience, and believe me, it's great for LAN's.
If it's not your sort of game, then wait for UnReal 2, a summer realise I think......Oooo, and Serious Sam 2!. :cool: