Gratuitious Space Battles is an excellently titles game, as it describes exactly what you get! This demo allows you to play three missions of this large scale strategy game.
This is a one-turn strategy game, in which you assign a fleet of space craft on a map, choose their weaponry and behavior, then let them loose on the enemy. I describe this as one-turn, as once you have set up your fleet, you have no more effect on the game. The Gratuitous Space Battle plays out based upon your strategic decisions.
This is unusual, but the detailed graphics and wealth of information you have during the battle makes it compulsive viewing. You can zoom in and out around the large battles, while your fleet is having constant conversation about your progress. The sound and explosive graphics really are cool, and it's pretty nerve wracking stuff. The setting up of battles offers lots to do for strategy fans and the detail obsessed, but if you don't care you can zip through the set up after simply placing your space craft on the map.
If you're not impressed by lasers and big space explosions, there is pretty much nothing to enjoy about Gratuitous Space Battles. The non-interactive nature of the battles may annoy some people, and perhaps over time they'll lose their attraction to explosion fans too.
Gratuitous Space Battles is an in depth strategy game with some stunning graphics, though it lacks any real time interaction at all.