I’d never heard of Don Doko Don. I don’t even recall seeing it on MAME. But I set about playing it (on Taito Legends 2) anyway, and then ended up completing it.
Like several of the games on Taito Legends, Don Doko Don is very similar to Bubble Bobble. You have a single screen per level, and one or two players have to defeat all the baddies on the level to progress. Where Bubble Bobble have Bub and Bob, dinosaurs that trap baddies in bubbles then burst them, this game has Jim and Bob, two bald men with mallets who bash baddies on the head, then pick them up and throw them (preferably at other baddies).
It was fun, although some of the 50 levels were bloody hard. Bizarrely, the only difficult boss was actually the first one, too, which almost put me off trying to progress any further. But I didn’t, and I won. Hurrah!