Thanks, I'm glad you like it!
To answer your questions/concerns:
- Upgrading the sword beyond level 3 is entirely useless. I was planning to add some range to the slash, but didn't get to it in time. The sword is very underpowered compared to the bow because of it. Your point about not being able to heal back is valid. Maybe I should have added some way to heal between waves.
- The fact that the enemies don't go after the treasure at high levels is a bug. I've not yet been able to pinpoint what happens exactly, but I think there's an edge case where if you kill an enemy while it's in a certain state (maybe taking the treasure, maybe running away with it), the treasure doesn't reset properly, and units will ignore it as if it's being carried by someone else. It definitely hurts the gameplay at later levels, so I think I'll try to find the bug after the jam and fix it.