I think you should change the text for the talk command to loot if you have no other talk convos. f you do, you can change something like 'Arena' to 'Loot' and make a LOCA event on the tiles surrounding the corpse with event IDs so that it can't be looted twice. Also, try making the corpse green. I was confused at first and killed it.
I had this happen to me while looking at the map during the prep screen:
The idea where without warning, a soldier can ambush-spawn and insta-kill you is definitely not Ragefest material. Absolutely do not do that.
When you open the chest, it doesn't actually open on the map. The tile change never triggers where it opens, so it just stays closed.
It's pretty buggy overall. I saw a few random light runes appear and disappear, another Midas spawned when the first one healed himself after a big, yellow box appeared on the screen, but I was one turn away from finishing. I didn't really matter.
Once again, I like your idea, but it was boring. I did restart when I realized I was at a dead end, but Midas never caught me once. The fact that I was shown the map in the prep screen made all the difference. I knew exactly where I was going. Maybe don't show them the prep screen and make cursor flashes on where they need to go? Don't show them the path to take, but don't leave them completely in the dark.
I took me 20 turns to finish the chapter. I only used one elixir.
I think you need way fewer traps (for less bugginess and more Ragefestesque gameplay) with a few more enemy units that need to be defeated. Also maybe consider adding an ally to two. Chapters with very few allied unites usually don't go very well from experience. This may be an exception with the maze idea, but just a suggestion.