I liked it. The boss design is scary and cool.
In terms of gameplay, the idea of distributing buffs and debuffs is cool, but it turned out that the boss received a buff all three times, twice for regeneration and once for increasing health. I think it would have been better to give a buff to the player and the boss at the same time.
The strong attack seemed much more powerful to me and I only used it, the bosses have large windows for attack and you can hit 1-2 times with a strong attack. I only used the crouching feature on the first boss.
The third boss is cool, but I think it is weaker than the first and second. I really liked the final boss, cool attacks, but the second phase seemed to me to be broken, he just lay there and did not attack.
Anyway, great job!