It is the only prototype for Snark known to exist. It is
believed that this is the last version that was worked on.
The game seems complete but still has a few minor bugs that
probably would have been fixed before it was released.
John stopped working on this game to start Superman. Atari
didn't have real lab loaner labels at this point so they simply
put a large white sticker over a production cart (in this case
Combat).