Pretty nice game, just needs some polish. Also I noticed that if you go against their knockback you can avoid taking more damage then once, so it's really good against bosses, my suggestion would be that if you enter their hit box you would take knockback +damage but if the player hasn't left the hit box a timer would start that damages the player every second(or something like that), because now you can kind of easily cheese the boss by standing on/in him pretty much. But it's a pretty nice game.
Thank you very much, brother. This is my first completed game. The problem of getting stuck on the boss is an old one. Knockback was one of the attempts to fix this. Other possibilities involve greater complexity that are still beyond my knowledge. I continue studying to improve the games already made and to make even better ones. Again, thank you very much for the feedback.