Good work here; you have clear ideas and know what you want to convey.
My general recommendation would be to use less harsh-sounding plugins/soundfonts.
- The "Main Menu" sounds so peaceful and magical—incredible.
- At first I wasn't understanding why the overworld themes felt so repetitive, but it's because they're dynamic, so they're fine in that sense, but I would recommend that the layers be more distinct from each other, or play with the rhythm of each one to create variation.
- The boss theme is well put together; I like those stabs, as well as the return of the choir like in the menu theme, and the metallic hits, like in the general combat theme. Although I feel that the lack of percussion or an accompaniment serving a rhythmic function takes away some of the intensity.
- The end-credits theme is really nice; it feels conclusive and is probably the most cheerful song of the bunch.
- My only comment would be that the shaker sounds too loud.