The art looks nice, and the boss are nice too. I like the effects of the first boss, the second have some really difficult attack but its fine. The gameplay are cool, I like the position swap mechanics and how you can heal from that. Also the music are nice too.
Tho there are some delay on the start button , player death and the boss death event. And sometimes the death screen and the win screen will stack together and you need to restart the game again.
But still, nice game!