Spent my night beating this with a neutral and then pure ending on Easier mode. It was a neat fun challenge, and it turns out tipping the scales is worth the warning the description alludes to both in story and gameplay.
Suwako fumo gave me the most trouble to dodge, conversely the easiest boss for me was usually Tewi fumo because you can hang around the side of the room with constant DPS, but even normal enemy rooms were a threat if played sloppily which is true to the theme I suppose, I don't think I was really conscious enough to try to focus through all of that. The fumos are particularly helpful upgrade shields once you get them rolling, though Flandre is an exception for that role.
I got stuck in a narrow corner corridor once that I couldn't get out of. Fortunately it was the very second room of the game.