Among retro gamers, you'll sometimes encounter the sentiment that "Mr. Do is just a rip-off of Dig Dug." I feel this is a simple-minded position to take. It's true that Mr. Do came out after Dig Dug ... but only a few months after, meaning they were almost certainly in development at the same time. Did someone at Universal get an inside peek at Dig Dug while it was in development? That's very possible. But also keep in mind that the largely forgotten Adventures of Robby Roto, which came out over a year before either game, was actually the originator of this whole dirt-digging framework. So it's really probably most accurate to call both games a Robby Roto ripoff, but Dig Dug had the best marketing and the longest legs thanks to Namco re-releasing it constantly, so it won the long-term mindshare award for any game that involves digging in the dirt while being chased by monsters.
Anyway. Maybe it's just my bias speaking, because I consider Mr. Do to be a better game than Dig Dug. It's one that I enjoy coming back to at least once every few years, whereas I think I've had my fill of the Dug for a lifetime already.
So our Mr. Do is a clown who served as the corporate logo for Universal in the late 1970s and early '80s. This was back when there was less welfare and clowns couldn't get away with hanging around all night on the streets with machetes engaging in juggalo antics, if they couldn't get full-time work at children's birthday parties then they made themselves productive by mining underground cherries and helping to control the population of dangerous penguin-dinosaur mutants.
Instead of pumping chumps, Mr. Do throws a ball that will careen through tunnels until it hits an enemy and kills them. It can kill any enemy on contact, but between the careening and a recharge time, it can be five or six seconds between each use. There's usually five or six monsters up your butt at any given time, so it's of limited use and has to be deployed strategically. The overarching goal is to collect all the cherries on each board, but bonus letter characters will periodically appear; hit them with the ball, spell "EXTRA" and you get an extra life.
Mr. Do has another bonus that is fairly uncommon for arcade games. While 1ups were a staple even in these early days, Mr. Do randomly has a diamond appear that gives you an entire extra credit if snagged! Giving you a full credit as a bonus is pretty damn rare.
With good sound work, pleasant enough graphics and gameplay that is a bit more thoughtful and strategic than Dig Dug, Mr. Do is really the dirt-digging monster-smushing title that should have gone on to longlasting fame.