i think there's something missing regarding the allegations of using MAME to cheat in Donkey Kong... what Billy can cheat in Donkey Kong in MAME and how?
old arcade games are not that easy to hack and modifying the game's code can bork the game. that's why most of game modding even today is sprite/model swaps, variables/number swaps. in fact modern games are easier to hack than old arcade games (I even have encountered a new game made in UE that has 3D models in the files unencrypted).
so what could use MAME to cheat? score multiplier/bonus multiplier/time multiplier? that would be an easy way to get caught. enemy pattern change,player and enemy hitbox? that would require a huge effort of changing the game's code and possibly bork the game. other than the flames, the barrels and the trampolines have only 2 patterns and they are random, only going faster and faster the more you finish the stage. lives? would be too much obvious. modifying dip switches? the only dip switch settings Donkey Kong has is the starting lives, how many coins per play and bonuse life and specific points
save and load states? these speedrunning troons, even Karl has been exposing cheaters splicing footage but Karl has never brought up any evidence of splicing footage regarding the Billy's supposed "Donkey Kong MAME run" on VHS
I think Karl and everybody else accusing Billy Mitchell using MAME to cheat in Donkey Kong still lack something. what advantage does using MAME bring to the game