Dangan GB is a short simplistic boss-rush/bullet-hell shmup by snorpung and nordloef released for the Game Boy to celebrate the console’s 30th anniversary.

Release notes:

Dangan GB receives a small update containing a few bugfixes. The music has also been balanced a bit. The game drains less battery now, so if you already downloaded the game before and plan to play on real hardware; you might want to snag this revision.