So this is fantastic and a great original idea and one of my favorite games I played in the jam so far. Two minor complaints:
My first impressions was "Why do you move on key-up and why does it feel like there's a delay in my inputs?" but idk it's sokoban so it doesn't really matter but you'd think you'd move on key-down. Or if you really like moving on key-up, from a game feel perspective key-down should at least acknowledge your input by animating the character preparing to move or something.
It can be hard to tell what block affects what. Does moving left-right give me health or take away health, for example. In practice this doesn't matter that much because you're not going to solve the puzzle right away from looking at it and it takes some trial to learn the things anyway, but it still just felt a little unclear sometimes.
But yeah fantastic, great and stuff.