Symphony

[Draco1962]

I have been playing this for a while. It is kind of Galaga meets Demons meets Bullet Hell meets your music. Available on both GoG.com and Steam for about $10US, I have spent more on worse.

Description from GoG.com: A mysterious entity is absorbing and corrupting your music before your very eyes. You must battle through your own song collection, discover items, customize your ship and fight bosses to liberate the Symphony of Souls and reclaim your music!

Symphony is one of the most music-driven games ever made. In this vertical shooter, re-experience each of your songs as it becomes a unique battlefield driven by intensity and tempo. Your music collection is now an item collection! Each of your songs contains an item you can discover, equip and upgrade. Fully customize your ship to reach score targets, upgrade items and unlock new difficulty levels. The cutting-edge music analysis algorithm used in Symphony adapts the game to any song you like! Supported file types: MP3, M4A & AAC (runs using QuickTime), OGG, WAV, FLAC, WMA, AIFF, WV, APE.

Get ready to experience your music on a whole new level! 

• Battle a mysterious entity that absorbs and corrupts your music as it plays.
• Discover, collect, and equip weapons hidden inside your own music collection.
• Per-song leaderboards and custom achievement/medal system.

[RIP-Felix]

Lol...a "neon lightshow of Galaga on crack". Made me snicker. Interesting Idea, not sure it would be enough to sell me. I need more of a hook than just a galaga clone set to my music.