I'd love to hear more about what you feel is missing — from my perspective, the game has accomplished everything I set out to do, and more. The visual style could be a bit more coherent, and the sound design isn't quite where I want it to be. Movement is still a little ways off feeling ideal too, I suppose...
I've definitely gone back and forth about the mobility upgrades. On the one hand, they open up a lot of additional level design space, and they can really aid in the feeling of growing more powerful as you play. On the other hand, I had hoped from the outset that I could build something that felt like a Metroidvania even without that common trope. That said, if I take this game any further, I probably will end up adding a handful of mobility upgrades to the level editor for folks to play with.
Thanks for giving this a play!