I love music games for some reason, but my biggest problem with them has ALWAYS been the available songs. I have distinct tastes as it where, and games like Rock Band / Guitar Hero generally only have 10-12 songs I really WANT to play through.
Beat Hazard, however, involves playing through your own music, and thats just awesome. You basically pick a track of yours (Mp3), then a difficulty, and the game generates the enemies and strength of your weapons based on the audio of the song. I am not exactly sure HOW it does it, although I do know volume plays a part.
Its an excellent game, and a fun diversion. Why not listen to your favorite songs while blowing up evil ships? Sounds like fun to me!
Word of Warning: If you like Jethro Tull dont play Dun Ringill on this game. Its...brutal.