There is a bug where after beating the final floor you can go the central tile in the back (where the stairs normally are) and replay the last floor. I think this would be an interesting feature if you could chose to replay the last floor perhaps even buy 1 health but no upgrades between each attempt.
 "Pawnbarian"){kind=icon}
Hey - this is actually a bit more of a proper feature since the last update. Try a hard refresh with Ctrl+F5!