A small detail for the original CI waves in CIU

If the waves from the original “Chicken Invaders” are going to be added to CIU, I thought it’d be nice to add a little detail: since in that game your movement wasn’t with the mouse and actually only with the left and right in that game, maybe in CIU there could be some sort of “Magnet” or “Force field” that prevents you from moving upwards and limits your movement to only left and right. This can also make the “Be quick or be dead” wave possible.