Hey, really appreciate the comments, thanks!
Yeah I definitely agree that armor and weapon loss causing problems long. It was something I implemented right near the end when I was trying to come up with reasons for the player to choose to start from floor 1 each run instead of always taking the shortcut -- if you take the shortcut you probably won't earn enough gold to have good equipment on your next run.
What i've been considering instead (if I ever decide to expand the game) is having upgrades purchased in town be permanent but more expensive, with additional temporary upgrades found as drops in the dungeon itself.