Get to level 5.
Get to level 10.
Get to level 20.
Get to level 30.
Get a perfect on Stage 3.
Get a perfect on Stage 7.
Get a perfect on Stage 11.
Get a perfect on Stage 15.
Get a perfect on Stage 19.
Get a perfect on Stage 23.
Get a perfect on Stage 27.
Get a perfect on Stage 31.
Get one of your ships captured by the enemy.
Save a captured ship and have double the fire power.
Get higher than the default hi-score.
Get to the second level without missing a shot.