Two years of consumer research. One thousand game testers. Thirty-five laboratory tests--close to double the amount many big-name titles have. Halo 3 was, according to Microsoft Game Studios Games User Research Group engineer John Hopson, the largest research project done by the division on a single title. Hopson used his speech at the Game Developers Conference recently to outline the mammoth testing process behind one of 2007's biggest hits, outlining what worked, what didn't, and how the final game changed as a result.