Cool game! I had fun on hard mode, even though you took away my ability to jump, after starting me off with the ability to jump. I think to be able to open the menu and not die randomly you could have a variable set to true when the menu opens (and false when it closes), and have the enemies check for if the value is true and if it is they can't move. But I kind of liked the aspect of having to time when you open the menu so you don't get caught.