Double-click the green flag after quitting from the pause menu. Arrow keys to move, z to jump/ homing attack. Down to slide. Down in the air to stomp. X to boost/ air boost. Enter key to open the pause menu. S to toggle debug mode. Press A in debug mode to debug move. When you restart the level, the screen will flash black. This is intentional, it *is supposed to* keep you from seeing all the stuff that becomes extremely derpy during the restart.