Aiguanachein is working on a very nice Game Boy Color platform game named Powa! The game will feature different worlds, music by sergeeo and certainly final bosses. After exchanging emails with the main author there might be physical carts, once the game is final.
We at PDRoms already had the pleasure to play the game and it plays solid and is fun, we would really love to see this game in final stage.
Canal Homebrew: Primeros Minutos a POWA! (Aiguanachein) Gameboy Color