Major grievances/errors;
The Quit button doesn't do anything.
Tengus appear some point after the third floor, and you need their move on the third floor to beat the Oni that always blocks the way to the staircase.
You can have fights in which all four of the cards that you can play are absolutely useless, and you can't have only one card type selected at a time, making it easy to lose without having the slightest chance.
There is only about a 75% chance that you leave the first floor with the Clench ability, so sometimes you have no change against Fantasy Males, by default.
Some enemies, that exist on lower-leveled floors, will spawn with higher SP than it says they can, when you move up. (i.e. 20/15) Likely related to other enemies on that floor having 20/20 SP.
You can't view what a card does (besides color) outside of battle, nor see the specifics of said card like you do when you first get it.
The Sound Effects control level doesn't change.
The SP counter visually resets to 20/20 every time you change floors, but when you open the V menu, you can see the correct amount.
Yes, I've tried and tried again to defeat the Oni. The hour I've put into it has produced absolutely nothing.
And apologies if any of the wording seems harsh; I initially began this a a frustrated rant, then reworded it before adding onto it and posting it.