Very basic screen zoom, max zoom is 2 times bigger (because of Scratches max 200% 'Size' feature limitation) and smallest is technically 1/100th of 1 because of Scratches 1% size limitation. (because 0 makes it disappear, and negative #'s flip it) 4 100% by me myself and I. Use WASD to move the objects, up arrow and down arrow to increase or decrease the zoom, and 1,2, 3 and 4 to go to present zoom options.