Can you imagine a game that combines Guitar Hero, Trackmania, Wipeout and some surreal media player style music visualisation? Well if you can’t then you could just download Audiosurf to see just what that would look like. Combined with Steam this game is just all kinds of awesome.
In addition to the fantastic visualisation techniques there are also two important things going on here. There’s the social networking aspect of who is playing what music and how well they are doing. There is also the extreme personalisation as you are listening to your own music.
As a tech note, if your game keeps saying that the demo has expired when you have actually purchased it, just restart the Steam client.
It is also another example of how well Steam Achievements can be used to set challenges and keep people playing. I expect all games to ape HL2 E2′s achievements strategy in the coming years.