You have a base and you get a random critter. Each critter has 3 units to it, one for each race. You bring it to the labeled doo-dad of your choice, and you get a unit.
Critters are generated at random, so it stays fairly even throughout the game.
The air critter can upgrade again after its first time into a different air unit. You use the units you get to fight it out with the other players. This game generates a battlefield around luck and micro, not a bad combination. Never before have I played a game similar to this, which is good. The cool sound effect always adds some fun to the whole scene.