I enjoyed playing it a lot. It's amazing you managed to create this much content in a month, good job. The controls are feeling very good, and the boss fights are kinda cool. The art is simple yet very solid and conveys the intentions of the characters nicely. You even managed to create menus and bindings! I think you really found the perfect project scope for this one-month jam!
The only gameplay problem I encountered is that enemies' attacks are quite hard to anticipate and feel a bit unfair, especially the first boss, but the fact that you can heal pretty often compensates for that.
Congrats guys, amazing job !