Truly dreadful - almost every element has been superceded by other (often older and cheaper) games
Frankly there are much much better games on the market if want to shoot stuff (such as CoD4, Crysis), much better games if you want atmosphere and story (such as Stalker) and much much better games if you want graphics (such as CoD4 and Crysis again).
The only excuse for this may be that Eidos were desperate to get the game out for financial reasons and ignored the developers, since to be honest it does feel half finished.
All I can say is, thank goodness I didn't pay for it but played a friends copy .....do not waste your money