There are two player slots; one for red terrans and one for blue. If only one person plays the map, all terran forces become red.
The players must defend the outpost against numbered waves of zerg, which are generated at the four corners of the map and attack from these directions towards the center. The first waves feature zerglings but later hydralisks, mutalisks, lurkers, ultralisks, guardians, devourers and defilers attack. The zerg forces can change their spawning patterns based on which units the players are using. For instance, using many battlecruisers prompts the zerg to produce more devourers.
The teal, purple, orange and brown broods each have a cerebrate (with higher-than-normal hit points) coordinating them. Each generates minions at the four corners of the map (not just their own corner). Destroying a cerebrate prevents the brood from spawning new minions. Destroying all four cerebrates wins the mission.
The yellow brood has numerous hive clusters and has powerful minions defending each cerebrate — four Hunter Killers, four Kukulzas in mutalisk form, one Matriarch, one Yggdrasill and one Torrasque. Whenever one of their defiler mounds are destroyed, it will spawn an Unclean One there. In addition, it spawns numerous overlords which float randomly about the map. When those are killed, more spawn to replace them.
If the players kill a kakaru, the game becomes somewhat harder.
- Blizzard Entertainment. StarCraft: Brood War. Vivendi Games. Map: Twilight Struggle. (in English). 1998.