Ah! That I might have a clue about... I had to jigger with the collision boxes on the party status UI when I was adding the status icons. It's possible I messed it up in general, and/or did so with the resolution Demon's running at for you.
Still needs fixing, but is far less intimidatingly weird.
Can you hit F5 in game and tell me what resolution it says it's running at? (Even a save file won't give me this, since it'll immediately switch to my computer's resolution
) Thanks again!