My apologies to the original subject of this thread...
Coasterpunk: The original Mr. Do (yes, he was a clown) was a VERY near rip-off of Dig-Dug. You advanced a level by either killing all monsters (either with the Power Ball, or by crushing them with the large apples) OR by collecting all cherries (6 sets of 8 cherries, 48 total). Once all monsters were out of the "monster generator" it turned into a piece of cake (if I recall correctly) by getting the cake, another set of monsters came out, as well as one monster with a letter on it. (the letter monsters would spell out E X T R A) By killing all 5 of the letter monsters, one per round, you get an extra life. There were no bonus rounds except for the killing of the letter monsters. I could play that game for over an hour straight, on one quarter. No coaster was involved.
I think there might have been more than one sequel to the original Mr. Do. I can think of only "Mr. Do's Castle." Perhaps the "coaster round" was on one of those.
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"X" marks the spot in 2001!