I agree with Buscadon, this is such a good boss battle theme. I could easily imagine this playing in a modern RPG.
I love the instrumentation and the nice repeatable structure is good for a boss battle. The organ is a stand out for me bc it gives me circus/evil clown vibes.
I would've loved to hear some other elements like a theremin or strings to give it more of a Halloween vibe but I think it does a good job of fitting a merry-go-round vibe.
I am also in love with the cover art! The annotations are 👌 Great job!