GTB differs from conventional Tower Defense in many ways. Firstly, you can play either side (attack/defense), secondly all the units are customised both simulation-wise and visually. Thirdly, the game has a built in map-editor and map-sharing feature to encourage widespread custom-map-making. Fourthly, GTB lets you save out your own attacking decisions, then play against them as defender. And lastly, the game also features optional 'adaptive' AI rather than just pre-scripted waves of enemies (although these are available as well).

Set during an alternate future where world war one never ended, and continues to be fought with mechs and laser-tanks, GTB blends hardcore strategy gaming with a light-hearted sarcastic sense of humour. The war has raged for 200 years, but our superior officers are convinced it will all be over this Christmas, however many poor beggars have to be crushed into the dirt to make that happen.