Love the whole mood of the game. Dialogue was intriguing. Boss design is very good, great that you managed to get in so much variety in attacks; all stages of the bosses felt very different.
Good level of difficulty, your take on the theme adds a unique challenge. Forces your aim to be reset whenever you move, and rewards quick aiming.
For improvements, I'd suggest tightening up the dialogue, maybe cut it by about 20% (a couple of conversations went on a bit too long). I'd also suggest adding a few frames invulnerability when you use the right-click dodge. As it is, I didn't find it that useful in the Elton Johns Ghost fight.
Overall, strong and stylised submission. Well done!