Codes:
At title screen, press any one of these words to do what it says:

techno -super arcade mode
weird -food ship nine arcade mode
enemy -use the enemy U ship in arcade mode
stealth -a stealth ship in arcade mode
unknown -a ship that I don't really know
nortshipz-another ship in arcade mode
destruct -a mini game not even based on the game

Hard Arcade Mode:
In v2.1 only, type engage at title screen for a very hard arcade mode (the difficult selecting is lord of the game).