Stack It Up is a physics-based stacking game. Each level gives you a certain number of blocks to place on the screen. You must stack them so that they reach the dashed line. Once you're satisfied with your stack and it meets the height requirements, press the check mark to start the test phase. Your stack must stand for a certain period of time as balls are shot at it in order to advance to the next level. Every two levels, you get an upgrade to make your task easier.