i've checked in one of the game sites & they reported that the game offered in kazaa is in fact full game but without movies & music. this is to keep the size(which i think is about 400+MB) low & attractive enough to download. what deathatthedoor said about the 6 hours of gameplay limitation is true. & u have to purchase the code for what i think is about $15($14.95 but then who cares for the 5cents) & winterfox did mention on the obvious possibility of the code being distributed illegaly.
So in a nutshell, you pay for a game without sound. Great.... :\
Better get it on the 'other' ways or simply buy it.