From Martin Hollis' wikipedia page(project head for Goldeneye 007): > Hollis remarked that he worked non-stop on the game, "[averaging] an 80 hour week over th

From Martin Hollis' wikipedia page(project head for Goldeneye 007): > Hollis remarked that he worked non-stop on the game, "[averaging] an 80 hour week over the 2 and a half years of the project", and that the team he recruited was very talented and dedicated even though most of it was composed of people who had never worked on video games. I guess the answer is insane levels of talent + dedication, and don't worry too much about domain expertise. Probably my favorite factoid out of there is that Goldeneye multiplayer was an afterthought, and basically one dude hacked it together in a couple of weeks at the end of the development cycle.