When I defeat a boss, if I don't grab the loot it drops quickly enough, the game will go "Game Saved!" and it will save my state from before grabbing the loot. For the beholder boss, this means that loading my game puts me on level 41 without the fire sword, and I die very quickly.
To solve this:
Put a high TTL on firesword and don't move to the next wave until it's picked up.
Make a bouncing arrow icon to message to the user that they must pick it up.
To solve this: