Armada Codes -

Continue game play
Press Start on controller two immediately after your last ship explodes to continue game play. Then, have player two quit the game and player one will be able to continue.

Extra credits
When you finish escorting a ship to its destination, stay with it after you are paid. The ship and the others will destroy enemies for you, leaving credits behind. At times, you can receive 200 to 300 credits before returning home.