Most what I could say is already echoed by other commenters, but I wanna talk about my experiences with the bosses. I think they're cool in concept, but leave a little to be desired in execution for me. The first boss is... rather dull to me. It's just a lot of waiting. You can't parry his barrage, so you're just having to wait for his big attack, which could happen anywhere between 5 to 30 seconds depending on how he's feeling with his barrages, and for a boss that requires you to learn parrying, I find it odd that only one of their attacks can be parried. I just found myself sitting in one spot, holding block, and turning left and right depending on where he is until he finally decides to give me an attack I could parry. Rinse and repeat until death.
The second boss I found to be a little better, but I feel like the game wanted me to use of the teleporting technique, but uh... Nah. Honestly, I think the second boss is way better suited to learn parry with since their only ranged attack can be parried without a problem. Best tactic I found was to stand directly under her, parry her ranged attacks 3 times, run to the left or right a bit to dodge the slam, and then head right back under her to rinse and repeat. I was encouraged to get potions, but I didn't need that with this strat. Enemies were a jump scare in the middle there and sent an absolute barrage my way, but nothing another parry couldn't fix.
And the final boss was essentially a third verse same as the first. It's the first boss again, but twice. Admittedly they use the big projectile as their default and having to time increasingly faster paced parries is cool and much more engaging than the first boss, but... that's all there is. You do that for two health bars, one being in a sort of pseudo darkness, and you're done. He's a God King but he's only barely better than a Cursed King.
I think a lack of variety is the core of the problem at the end of the day. I think having more attacks that keep you moving and maybe more opportunities to parry other attacks could go a long way in making each boss more interesting and active than just sitting in place and waiting. Regardless though, I do think everything sounded nice and I found the gameplay to be fairly fun and reliable despite not really feeling like I was doing much in the bosses. Art was good and everything stood out well, nothing got lost in the background, attacks were always visible, and I did still enjoy my time. Good on ya for making this, it was an enjoyable little game here.