Since Mappy: The Beat has been on my feed lately, (love it, btw), I wanted to lore-dump about the Namco universe and Mappy and Dig-Dug. (I had a phase when I was about 13 where I was obsessed with the classic Namco chars and Namco X Capcom, still am, lol)
So, for starters, around the same time they were doing Shiftylook, Namco unified most of their sci-fi shooters into one universe called United Galaxy Space Force.
Among the dozen games now having their lore merged together, were, Ace Combat, Galaga, but the focus of this post, Baraduke and Dig Dug.
Dig Dug might seem out of place at first, but there's an explanation, in the Mr. Driller games, he's the father of protagonist, Susumu Hori. (As well as Susumu's two siblings.)
(You might remember him from another Shiftylook project, Namco High)
But the kicker is twofold, Taizo Happened to marry Tobi 'Kissy' Masuyo, the protagonist of Baraduke.
(As a side note, her game predates Metroid by a year, slightly preempting Samus's status as one of the first major female gaming protagonists, though Samus is still largely the codifier.)
So what's the other bombshell? They're divorced. As it turns out, in Namco X Capcom, the pair had a rocky divorce, and Tobi, during the mission where Taizo/Dig Dug is recruited, isn't entirely happy to see him, and wildly, this change in storyline stuck for the subsequent Mr Driller games as far as I can tell.
Going into more detail, Taizo and Tobi were members of the same 'Space Border Patrol' (Which I imagine to be similar to the Space Knights in Tekkaman Blade) until a mission ended in a complete massacre that left the pair as the only survivors, and had a fight afterward, splitting up.
The crazier part is that there was a prior Namco crossover RPG, Namco Super Wars, (a Wonderswan game) that also featured Dig Dug, and coincidentally Mappy, as secret characters, and in -that- game, Dig Dug is still married, and while the games aren't strictly related, given Namco and Banpresto's penchant for crossovers and lore, there's nothing to necessarily say it's not a prequel in a sense. (Also bare with me I'm getting this tidbit from a translation on Namu wiki so it's a bit shaky)
So where am I going with all this? Basically, Taizo/Dig Dug, in Mappy, which isn't show to strongly contradict any prior crossovers, is already a divorced dad. (Which Shiftylook's comics even reference) So he's single, and Mappy, meanwhile is a disgraced cop.
In essence, Tunnelrat/Mapdug is a ship that could easily fit into canon, with little to no issues, AND it would also be Boyfailure old man Yaoi.
Go wild, y'all.