Next Generation reports on the risky choices Rare made with Perfect Dark Zero. They actually began stamping the discs before the game was certified
so that they could make the Nov. 22nd launch date. From the article: "The certification process is the final stage a game goes through before manufacture. Microsoft's team picks through the game making sure there are no bugs, that menus all work correctly, and that there are no compatibility issues. Games that fail, even in the smallest detail, are sent back to publishers and developers for changes. The process can take days, or even weeks."