UPDATE: Beaglepuss called me with some news...
Sadly, the EPROM was mislabeled. Instead of owning a Marble Madness prototype, he actually possesses a prototype of RBI Baseball. All is not lost, however. You can listen to songs from Marble Madness when pitching. Remarkably, all of the players on your team resemble marbles with stubby appendages.
Beaglepuss said he will provide more info when he has the opportunity.