1) After passing level 10, wait 25 seconds on that screen, and a blue ship will appear. Shoot it, and you’ll be sent to secret levels.
2) Before you press start, Press 1 for level 10, 2 for level 20, 3 for level 30.
3) Expert Levels- To enter the expert levels:
-Wait 30 seconds between levels 30 and 31
-Shoot the Blue Secret Ship that appears
