Destroying space ships has never been cheaper with Gratuitous Space Battles, as the intergalactic strategy title is now free to play on Steam until Sunday. If you love playing the game on your PC or Mac, it's on sale through February 25th for $3.75 and $4.75 for the complete pack, which includes all of the downloadable content.

Considering that Gratuitous Space Battles is normally priced at $14.95, that's a solid discount for the game. The object of GSB is to build up your fleet and tear the enemy apart with concise strategic thinking. Gamers expecting a muscular shoot 'em up should look elsewhere, as it's a title that, according to creator Cliff Harris, is more like a tower defense game than a real time strategy title.

"Imagine tower defense, but with moving towers you can design from scratch, in space, with cool laser effects," said Harris on the game's official site. "That is a fair approximation of GSB."