Sorry for taking so long to reply.
Is there a particular reason why swinging the sword from below to up feels strange? It's an important game mechanic used in the progression. Each weapon has a unique reach, so some enemies that can be hit with the katana may not be reachable with other weapons, and vice versa. For instance, the katana can't hit enemies from above, this is also valid for breakable walls.
I've been thinking for a while about making the world dungeon-based, it would be a great nod to the game's main inspirations and also give more room for visual and music variety, but the problem is the lack of connection between dungeons, it would certainly limit the level design.
Currently, the idea is that every area is a mini world, with different "biomes" and thematic. The Cursed World is the first area of the game, it is supposed to be a "twisted forest" with labyrinthic design, nonsense geometry and risky room layouts, it's a very weird design choice, but it was meant to be a place to be explored later in the game, having at least one easy path that would lead to the second area, the Grasslands, which will be far more welcoming than the first.
This is already present in the game, the problem is that almost nobody managed to do that, the Cursed World is difficult but not in a fun way, it's not as labyrinthic as I wanted it to be and the excess of platforming challenges makes it tedious to explore. I wanted to know how the player experience would be, I understood that these weird choices would hinder most people from making progress, but the game also failed to hold their interest and they soon gave up. I don't intend to change what I wanted for the first area, but to work on it in a way that isn't as frustrating as it is now, and balance it so that at least the easiest path is achievable and the rest will intrigue people to return later or to keep trying if they have more patience/skill.