I've played this before in a previous demo day, I don't know if you had other playable characters then but regardless they were fun to try out. I don't think you had the shield boss either, that was also fun.
One criticism is that the bosses and enemies have low IQ, so there's no real challenge to the game. I also never really used other characters or special abilities. Brave's (the guy with the sword?) basic attack was enough to get through the game easily.

Only bug I ran into was both times I beat the stage boss, giant text would show on the screen that I couldn't read.

- menu was hard to operate on keyboard, seemed locked at first for a time (while the music was playing?) and then inverted ("up" selecting bottom button and down selecting the top one)
- the controls for keyboard are kinda uncomfortable, i suggest jump with W, and use IJKL for the rest, possibly U and O. space is better used either as a menu or as a way to interact with the world
- bomb's default attack / bullets did barely any damage at all

other than that the game is great anon