I managed to get through 90% of the content before getting stuck. I had the heartbrain, but couldn't figure out how to continue because I wasn't able to find the button for the stomping device (which I did find, but didn't know how to activate). So I peeked at Somdudewillson's video to see what to do next, but that was pretty much the end :D
I love the verticality, it really is a great addition to the game. It also looks quite nice, but same-y. I got lost many times, and there wasn't much guidance on what to do or where to go next, as it felt like one giant area with everything scattered about and accessible through multiple pathways.
Combat could use some polishing, I think. Auto-cycling characters was a bit confusing at first, especially when the mage is out of mana, as nothing happens then and you have to manually select a new char. And I preferred to pick enemies off from a distance with ranged weapons, so I had to keep reselecting that character continuously. So it felt a bit clunky. And while I realize it's quite common in crawlers, I don't like the step-forward-then-instant-hit-then-back-up gameplay that much, as it feels cheap.
Character building feels way overtuned, as levelups are so common and adding a stat point restores all resources, which also makes combat a breeze and the potions only useful as pressure plate weights :D But I know, better have the game be too easy than too difficult, but because of this the combat didn't really do it for me.
Wish I could've swapped AD with QE though :D
Overall a pretty solid game! I think some guidance could help, or perhaps restructuring the map to make it feel less chaotic would help. Things like adding a note or a sign at the giant stomping device with a hint on how to activate it. Some more flavor would also add a lot to the world, I think.
Good stuff!