Sorry that you encountered that game-breaking bug after being defeated. I'll look into squashing.
Thank you for playing through my demo, though. I'll looking into adding an option that allows damage numbers to stick around longer. I'll add in a hint that explains the functionality of WHIFFs versus MISSes.
The mansion was meant to be a pretty hard dungeon-crawling trial so that's why I made it so big. I wouldn't say I wanted it to be "tedious" but it is supposed to be tiring. I'll add in a way to buy CoffDrops at least.