Thanks for playing, and for the kind words! :D
Yeah, I'd say that's somewhere around 1/3 :) That section with the vertical shaft and sea slugs I actually think could do with a little tightening up XD And yeah, I think platformers tend to feel a lot better on controller. I play quite a lot, but despite that I can end up struggling on keyboard! We tried to match/take inspiration from the keyboard controls of other popular Metroidvanias/platformers to help, but I think they still add to the difficulty :)
Thanks again!