Differences between game versions

Many games go through several revisions, usually to fix bugs. Here's a partial listing of ROM revisions.

Defender - White, Blue, Green and Red versions

• White was in the prototype games. It is a 10-chip version which did not have a ROM test, and the RAM test was incomplete. When the game is turned on, the top high score is "DRJ 20000".
• Blue and Green do not detect all RAM bank 2 errors. Blue consists of 10 chips, while Green has 11.
• Red works with upright and cocktail games, and credits are retained after power down. There are also more liberal adjustments for play difficulty. There are 11 Red ROMs. (ROM 5 is not used).

Joust - Red, Yellow and Green versions

• Red and Yellow have the 'pterodactyl cheat'
• Red has default high score of 107212, Yellow and Green are 109102.

Robotron - Yellow w/ Orange stripe and Blue versions

• Yellow/Orange has default difficulty of 5, demo calls Quarks 'Cubeoids', default high score is 131682.
• Blue has default difficulty of 3, default high score of 151782.
• There is also a modification to the Blue ROM image that fixes the 'shot-in-the-corner bug'.