For those out of the loop, people have been sharing screenshots of the screen transitions from Mitchell's videos and MAME since at least 2018 as evidence he cheated. This isn't new information. What is new is that rather than simply showing the screenshots, Tanner Fokkens has dissected the code from the original Donkey Kong ROM to prove that the footage could not have been generated from the original cabinet. He then analyzed the MAME code to demonstrate why MAME renders the way it does to prove that Mitchell's footage matches a version of MAME that would have been available to download at the time the footage was recorded.

This is similar to when the speedrunner OmniGamer analyzed the source code to Dragster to prove that Todd Rogers faked his world record footage and subsequent Guinness record.