Fun collection of different styles and sounds! I think you could potentially get around a lot of the awkward sound of some of the instruments with some expression automation (someone mentioned the accordion). I think the sounds work for what you're going for, just a bit more expression in the articulation and phrasing would go a long way (if the vsts allow it that is, I try to always use instruments with a good response to velocities and with an expression parameter to automate). Not sure it'll help the accordion countermelody in menu theme, that might just be something for a different instrument to pick up. Ngl I really wanted to fit accordion in my soundtrack too but had a similar issue with expressivity.
The fusion of the styles communicates the fusion of game genres really well, it was a fun listen!