Thanks for playing! Sorry for the late reply.
I worked on the performance a bit in the new version, hopefully that helps.
Some dungeons have both interior and exterior floors, and the one you get is random.
I reset perk levels every time I rework how they work, that's why you had to reassign it.
Some attacks and abilities change depending on what weapons you have equipped. So Fiera's Whiteflame Embers make her shoot sparks instead of flames, for example.
The chest reward thing is being reworked, since it's a bit weird like you said.
Thanks for finding the top bar bug, I've fixed that now.
A tip for the level with the wisps (slimes) is that you can step out of the rifts to clear out the enemies and then back in and keep sealing it, it doesn't reset when you step out.