Small bug in home screen. If you load up game when Yui have already gone to sleep, she might be sitting out of bed and when clicked brings up the usual h-scene/sleep menu as if you clicked her while she's sleeping. And if you click cancel, she goes back to bed.
In Secret shop, when selling panties, it says "PANTY_NAME_KEY ???" on the button.
Improvement:
Add "Give up" button in combat, if it seems you won't win. It's pointless to wait for 10 turns.