I did a search on this site and couldn't find anything mentioning this game, which is unfortunate because this game is a gem. I don't know if this game necessarily meets the criteria for an "obscure game" because it was released by a AAA publisher and the developer (Irrational) later went on to produce Bioshock.
Despite that though, this game is pretty obscure anymore. You can't buy it at all legally anywhere, save for one copy that's on Amazon for like $140. After seeing what Ross did with Bip Bop, maybe Ross could convince 2K to actually sell their damn game again.
(also, shameless self plug, I'm working on a pretty huge mod for it, SWAT: Elite Force, go check it out, it's pretty awesome)