Total Annihilation is a science fiction real-time strategy video game released in September 1997 for Microsoft Windows and Mac OS by Cavedog Entertainment and distributed internationally by GT Interactive.[6] Two expansion packs were released in 1998, The Core Contingency on April 29 and Battle Tactics on July 20, while a medieval-themed spin-off called Total Annihilation: Kingdoms was released on June 25, 1999.