I like the productivity of entering a game jam to make a soundtrack you were already going to make for something else, and it seems that the game you guys are making is going to be pretty cool.
Using the gameboy sounds for your music is pretty limiting, but it seems that you know your way around it and can make it sing very nicely.
My favorite tracks are the last three, with the Fire Temple being my absolute favorite - for some reason it sounds very march-like to me, but i can't quite put my finger on it, except for the kind of marching snare. idk but i like it.
I also wanted to say that the pixelart looks fantastic, so props to the one who's doing the art.
Overall, pretty nice submission, it's making me kinda interested in the actual game.