The game uses the arrow keys and not the mouse, and you're constantly being pushed to the corner. I'll try to add a visual for it. I have no idea about the full screening stuff though.
OHHH when I saw cursor in the instruction I assumed mouse. Maybe you can edit the instructions on the itch page with the keys so everybody knows. Maybe I am just dumb. But some of these games are mouse, and some are keyboard. I don't want anybody to miss out on your game. I'll try playing it properly in a bit.