The HP system in this game is seriously stupid. No matter how much you upgrade your HP you ALWAYS die in 3-4 hits, wtf? Why even have an HP bar then, why not just replace it with hearts? For example on the SECOND boss in the game, you die in 3 hits, and the invincibility frame is like 0.5sec. Why in the world do you make the SECOND boss in the game so difficult? Why does everyone do SO MUCH DAMAGE?? You literally die under <2sec from simply touching anything. You might be able to take ONE MORE HIT if you spend ALL your points into HP, at the END of the game, seriously. Each point put into HP does pretty much nothing.