endless size

It's actually LMB on the right or left half side of the screen to decrease or increase

I appreciate casimodo's clarification! I think that the game would be better if the controls were LMB and RMB, though, or up and down arrows. With the current setup, the likelihood of getting your cursor offscreen, or not far enough to the left or right, is annoying. With tweaked controls I could see it being a fun, quick game to play.