Try the following to gain access to the first four levels (the last level, level 5, is only available when you complete level 4): On the level-access screen, place the “LVL” mouse pointer in the far bottom right of the green quarter screen. The bottom “L” must be
positioned in the corner with pixel perfect precision (two pixels on the pointer will be hanging over the edge to the right). Click the left mouse button, then shift the “LVL” mouse pointer to the very
top left of the screen (as far as you can physically move the mouse to the top left) and click the left mouse button again. Now you can get 12 lives at any time by pressing ‘F4’ during the game.