Mark's most prominent credential (and one he eventually disavowed) is having worked for Blizzard Entertainment. Between 1998 and 2004,
he was credited for working on StarCraft, Diablo II, and vanilla World of Warcraft. Mark would later claim credit for WoW's initial success, which has yet to be corroborated.
In 2005, Mark left Blizzard to pursue his own projects. While it appears that he left the company on good terms, he has since
framed his departure as a virtuous protest against layoffs and the "corporatization" of the industry.