On a far away planet, three races fight for control of the few landmasses available: the marooned Meccs, who specialize in firearms and other things that go boom, the mystical and cold-blooded Reapers, who were the original inhabitants of the planet, but were forced to live in the sea by Kabuto, the third character; a truly gigantic monster with a ravenous appetite and a fondness for performing wrestling maneuvers on those the size of his hand.

You can control any of these races (although in the single player mode, you have to progress through the storylines of the Meccs and Reapers first) in their bid to be the dominant species. Each species varies in the way they play the game and have vastly different types of attacks available to them.

Giants: Citizen Kabuto is an action/real-time-strategy game that emphasizes action. While there is base-building and resource management for most of the races, it is done through a simple to control interface and one or two keystrokes. The majority of the game is spent in a third person view (first person mode is available) jet-packing/warping/leaping about the 3D landscape. Single player sessions consist of missions with specific goals, such as rescuing Smarties or recovering lost items. Multiplayer options include standard deathmatch, capture the Smartie (flag), the above with basebuilding as an option.

Other creatures also inhabit the islands. From the meek Smarties (who are employed to build your bases or eaten as a primary source of protein, depending on your species), to the cow-like vimps to the deadly rippers, the fauna of the planet will either try to kill you or avoid being killed/eaten/captured. While not so energetic, the flora of the islands can be crushed, knocked over, or burned in careless combat (or by Kabuto not paying attention).

Game controls are similar to Shiny's MDK and can best be described as a simplified shooter interface. You can run, jump, turn, shoot, and strafe. Beyond that, a half-dozen keystrokes are all you need to play (and some, like Kabuto's howls, are for fun and show).

The alien world in the game is bright and presented with vibrant colors. In addition, the game tries to maintain a humorous streak. The single player game has goofy dialogue and a few jokes spread along its story line and even the multiplayer is lighthearted, with Smarties cheering you on as you carry them on your back, among other little sounds and nuances.