It's a good stand-in, however. As well as being the most popular game here at my Uni right now.
One of my friends is most of the way through constructing a level for it that he calls "radioshack" - which is where the corps are trying to take out a Punk radio station hidden beneath the dance floor of an underground nightclub, built underneath a highway that was in turn built right in the middle of a residential district (they seriously just shoved down one of the flyover supports in the middle of a road without any regard for who was living or driving there).
It's pretty awesome. VERY awesome, in fact. in some ways, it looks to be better than Vaccine