I think when you thrust up there should be a noise, such as engines firing or made a warp noise similar to that heard in Star Trek. Also the game should have intermittent music. A great website for finding Royalty-Free music for use in videos, movies, and games is incompetech.com. This guy has some great music and a lot of it. I'm sure some of it would go great in the game. Overall I really enjoy playing this game and keep up the good work schema!
-JohnBrokenBridge
-JohnBrokenBridge