During the Music Hack Day Stockholm 2013 hackathon, me and mandy forked Deathtroid into Super Mutroid (full source code), added EchoNest and Spotify support, and made a Metroid music game.
You can download it here (requires Mac OS 10.8): Download from cl.ly
From the Hack project page:
Music/rhythm platform game with a Super Metroid theme
Description
Plays a song through Libspotify and downloads song data from EchoNest. Generates obstacles based on the beats in the song.
How to play
W - Jump
S - Duck
When you start the game, enter a player name to the left and your Spotify login details to the right. You can also enter a Spotify track url in the text field under the Login button.
Then just press "Create Game" and wait for the song to load! (The character will automatically start running when the song has been loaded. If nothing happens after several seconds, the song you entered probably isn't available on EchoNest.)
You die if the character runs into the spikes. If that happens, press any key to restart. If you want to enter another track url, you have to quit the game and restart it.
Known bugs
Sometimes crashes when you press Create Game
Flickering character
You can jump through the spikes that you are supposed to duck under
