Thanks for the constructive criticism. I'll address each of your points in order:
1) I can see where you're coming from, but unfortunately I can say right now that most enemies will not be getting additional scenes. While indeed most of them can boil down to "getting dicked" as you said it, truth is that for most people that is honestly good enough. Besides, it would be an herculean effort to have not only more than just 1 scene for all enemies, but also coming up with totally unique scenarios for each of them. That said, this is something that I'll definitely keep in mind for my future next project.
2) Agreed, some of the later bosses become too much of a "bullet sponge" as they say, with too much health. This is something that I'm aware of and when I do the final balancing pass of the game I will tackle and resolve this issue, either with more easily accessible upgrades for Maya or with better balance of the boss' parameters.
3) Yeah this ties up with the above point: since the game is still in an alpha state of development, I simply didn't give much care at all to enemy/boss balancing, which is something that I have plans to do in a near future once I'm closer to completing the development of the game.
I find the game not very difficult, especially because some power ups do become busted (dash bypassing mobs, invincibility bypassing the spiky dungeon area , shockwave clearing all mobs on screen).
And I do want it to be difficult because I want to get those delicious game overs without playing bad on purpose.
That being said, I agree that some bosses have too much HP, and some bosses ramp in difficulty to the point of nonsense
(Mausolea overwhelms you with spawns and flies all over the screen, gives you no time to slash back at her. The Witch to the lesser extent, still too resilient, but at least she gives windows to attack her. On the other hand, Werewolf needs to be tougher~)