A PC/Dreamcast follow-up to TKG, entitled Alien Breed: Conflict (sometimes ABC or referred to internally as Alien Breed Action or ABA), began development in 1999. The development was cancelled due to the size of the project. To date, ABC remains as the only title in the series that was developed specifically for the PC and as the only PC game in the series developed solely by Team17 (the PC version of Alien Breed was ported by MicroLeague, while Alien Breed: Tower Assault were ported to the PC by East Point Software).
According to what little information there is concerning this game, ABC was also planned to be a first-person shooter and, presumably, would have followed on directly where TKG left off.
Read more about this topic: Alien Breed 3D II: The Killing Grounds, Cancelled Sequel