Linux Demo for Mammoth Gravity Battles. 5 Levels to try out.
PC Demo for Mammoth Gravity Battles. The demo has five single player levels from the campaign/story mode. The first three are 2D levels where the movement of ships and bullets is all flat, on the 2D plane. The last two are so much more difficult. There are two target practice levels where you aim at targets that don't shoot back, and three levels of combat.