Mammoth gravity battles has a brand new website, with loads of screenshots, details about the game and a brand new playable demo. Check it out at www.mammothgravitybattles.com .
The new demo, shows off the three dimensional mode around a one star solar system in a single player battle game (you vs the computer). You both have two ships and basic weapons only. Try out the different weapons, see if you can hit a power crystal to get access to more deadly weapons. I've kept the AI level at medium, so it should be possible to win, but not a pushover. Best of luck.