Thanks for playing and recording, I'll try to watch some of it =). Dungeons are procedural (I took and existing generator and tweaked it only a little bit for this, adding the two mimics per level and marking some areas as "indoor" to get a different tileset), and pull from like 15 tileset flavors - since the assets were there, making a new wall/door/floor/secret/detail combo only took a few minutes each, so I couldn't stop, even though most players will only see a handful of them :D.
And, yeah, stacking lots of hats of one color later can definitely block most damage, though each floor has at least 2 colors of enemies so you'd have to keep swapping to really abuse it. In the post-jam version coming soon I increased the "in combat" range that blocks inventory usage to the same as the range that triggers multiplayer syncing, so it makes it slightly harder to abuse (and, more importantly, you can't slow down other people if you decide to do so).