"... default dipshit eh switch setting of MAME ..."
Is it just me that is offended by that statement?
You are strange people. This is a VERY common pun about DIP switch mess. E.g. DIPshit is the name of a known synth mod to manually change the preset sounds of FM keyboards by inserting a DIP switch block between CPU and FM soundchip data lines.
I think I have found now the hidden mode in "Pucman", which seems to work somewhat like video poker; but I haven't fully figured out how to play. Using coin slot button 6 or 7 (instead of the regular 4 and 5) fill credits in (displayed at PUCMAN) and start gambling mode. Pressing now start will bet money (each a credit, makes POINTS increase by 1 and number below HIT by 500). Pushing joystick up makes pacman encircle the cage (eating 5 ghosts) and 5 numbers appear in the ghost cage, those can be selected with left/right and entered with up. Rarely now another number appears in the upper right (when player has won?) that adds to the EXTRA display (kind of jackpot or won credits?) and in the cage you can select "small/big" (betting on something?). With numbers in the cage, pressing start removes some and instead displays ghosts to be eaten, which may be like selecting cards in videopoker. If the credit counter reached zero, setting further money will withdraw it from EXTRA (the won money). If this is gambling, I don't know if the EXTRA contents can do payout through the coin return chute or if in illegal arcades the player would call the operator to give the money. I am not familiar with that kind of hybrid games.
In Germany we have "Geldspielgeräte" (recreational gambling machines) those often used to have spinning discs (e.g. "Rotamint", "Merkur-Disc") and gameplay resembles casino slotmachine but is slower and eats way less money per hour (and is legally required to payback a certain percentage per hour). Until 2006 each machine could only be legally used commecially for 4 years and then was doomed to become e-waste (unless ending in hands of collectors or party rooms). Nowadays successors have LCD screens and may use the same games like online gambling (but tweaked to German legal requirements) and typically can be only rented by operators. Possibly even the hardware is some kind of generic Android online device running a specialized app.
some (german language) info:https://de.wikipedia.org/wiki/Spielautomathttps://experts-it.de/files/PP.pdf
On Youtube I saw a casino car racing machine that looks like a regular 3D arcade videogame cockpit but withdraws a credit into the integrated slotmachine every time you overroll certain symbols... - What a money eater! By legally limited licenses and often changing laws, gambling games are likely even more shortlived than videogames and worth to preserve. Perhaps in 100 years mankind will be mentally or genetically upgraded to loose susceptibility to gambling and Las Vegas became history. Existence of gambling says much about what an illogical species we still are; future people may shake their head about us when studying such games.
I tried also the other secret gambling games mentioned on the page:
The Space Invaders (unksig.zip) is quite fast but at least I reach level 3 (feels like freakish Commodore VC20 stuff - I like that). Like Pucman, unfortunately it clears score too fast and keeps no highscore. The gamble mode seems to be a simple video poker variant with numbers instead of cards. (Shoot the objects = cards you don't hold.)
The Tetris mode of "Cherry Master" feels like a very sad Atari bootleg (monophonic melody, bricks only green, no animations, initially too slow etc.) - possibly intentionally boring by design to deter people from playing the non-gambling mode too long, because it didn't bring much money to the operator.
The game "X-Plan" (although marked defective) does seem to work, but (I don't know if this was again intended) looks like a very boring war plane shooter from a wannawii (SunPlus based chinaware) console. The gambling game again seems the same kind of primitive videopoker variant like in the Invaders (mark the planes = cards you want to hold). To toggle between both games you apparently need to hold 2 of the 3 buttons simultaneously; the one with title screen is the gambling. I hope this wasn't too off-topic.