Best I've ever done on the one I have at home (iirc, the rules were and still are: piano and slot machine set to "hard", extra balls enabled, first at 12 robots, second at 55, 3 dead ends, normal spiral, 4 balls in gumball so 7 in total, no buy in, special gives points, 0 door spots) was 4.2 billion. 55 minute game. Next best was 3.5 billion.