it isn't bad. the compression techniques for landscape and buildings, plus character modesl moving around make this look brilliant on a decent AGP, even an ati9600xt 128meg card makes this play on maximum almost graphics. admittedly, a nvidia gf4 mx440 to achieve frame rates of the ati9600xt has to have the graphics down so far it looks like a very fast moving original Half Life engine
the main problem with the game that stops me liking it (i had the game off a mate for 2 days until i gave it back to him) is that the game plays on "rails" no full free 360degree exploration, you must go certain directions to complete your task. going off route you find yourself blocked with no abilitiy to complete a mission in a different manner.
it's worth the money given the current state of the gaming industry i suppose, it's nowhere near as poor in implementation as doom3 anyhow!