Billy Mitchell, a gamer known for his high scores in various 1980s arcade games, has been stripped of his high scores in the game that he’s best-known for – Donkey Kong. The Donkey Kong Forum, a website that tracks performance in the hotly-contested game, removed Mitchell’s scores from its list after an extensive investigation showed that they were obtained via emulation.

Moderator Jeremy Young showed video evidence that Mitchell had achieved his multiple scores of more than 1 million points by using the Multiple Arcade Machine Emulator (MAME) rather than on an actual arcade cabinet. The proof lies in how MAME renders new levels versus how the arcade machine does; a frame-by-frame analysis shows that Mitchell had been using the emulator.

Using MAME versus using a legitimate arcade cabinet creates differences in how the game is played, particularly with regards to timing and controls. MAME also allows players to record and replay inputs, which essentially could allow for splicing together multiple runs to create one record-breaking attempt.

This is significant because of how Donkey Kong awards points. When Jumpman/Mario smashes enemies using a hammer, the points are doled out in a random fashion. Mitchell’s submitted videos showed an abnormally high amount of points being awarded for those smashes, which led to speculation that emulation was being used in order to manipulate the game’s internal random number generation.

Mitchell has long been somewhat of an infamous figure in the video game world due to his boisterous public persona. He was also framed as somewhat of an antagonist in the 2007 documentary The King of Kong: A Fistful of Quarters, which saw Mitchell face off against Steve Wiebe for the top Donkey Kong spot. Mitchell first made a name for himself in the 1980s, when he became the first person to reach the “kill screen” in Donkey Kong in ’82, and the following year did the same in Pac-Man. He has held various gaming records over the years in multiple games of that era, including Mrs. Pac-Man, Donkey Kong Junior, Centipede, and BurgerTime. Mitchell has continued to submit high scores in the many years since his original feats. He has also seen numerous honors over the years, being named as one of the 1983 Video Game Players of the Year by Twin Galaxies, and being named Video Game Player of the Century in 1999 at the Tokyo Game Show; Mitchell became the first video game player to receive a Topps trading card in 2008. Parody characters of Mitchell have appeared in the feature film Pixels and the animated series Regular Show.

The current record holder for Donkey Kong is Robbie Lakeman, who just recently set it on February 2, 2018 with a score of 1,247,700. A notable difference between Lakeman’s score and Mitchell’s is that Lakeman livestreamed the attempt via Twitch, and did so by having an external camera pointed at the arcade cabinet’s screen.

A more in-depth breakdown of this development can be found online at Ars Technica.