I think most of what I had to say has already been said, but I'll mention two things that IDK if other comments have said yet:
1) For the pearl UI, it would be really nice to see what it does when you unlock it, instead of having to navigate into another UI to even know what it does (and also unequip it there). Maybe when you obtain one it could also have an option, like "Equip now?" or "Keep current pearl."
2) It felt kind of bad to not have any marker for completing, e.g. the snail. It seems like each map marker should be checked off even if it doesn't award a pearl, as otherwise it's hard to know if I actually made progress or not.
I do have to applaud the variety of enemy mechanics I saw. Especially the Arba was fun.