This score is the result of a computer bug. I played Zenji on real hardware with Atarimax cartridge, then at about 30.000 points I earned for every round 10,000 extra points and so almost endless lives. I played further to learn more about the game. The difficulty doesn't improve a lot, so it was easy to walk through the levels. I stopped at 1 million points, so I think the score cannot be rolled.