Positech Games, the geniuses behind Gratuitous Space Battles, are back with their new game, Gratuitous Tank Battles (GTB). Set in an alternate timeline where World War I never ended, GTB on the surface is a just another tower defense game, but behind a seemingly cliche exterior is a deeply customizable and replayable game. GTB allows players to play as either the attacker or defender, seeking to break through no-man's land or break the will of the enemy horde. GTB also features a deep unit customization system reminiscent of GSB that allows you to tweak your attacking units, infantry, and defenses to your heart's content. Almost two games in one, GTB's demo gives you a good taste of what the game offers, and if you're a fan of the tower defense genre, then this demo is certainly worth a try.