Due to the holiday on Monday, we haven't had a GameSetNetwork round-up - of neat original articles on Gamasutra, GameCareerGuide, and our other sister sites - until now. Which means there's a whole heap of stuff to get through, headed by John Harris' 'Game Design Essentials' entry on Atari. Also hanging around in here - some top-level chats to senior types from Valve, Epic, and Midway, as well as a good piece on agile development at Large Animal Games and a discussion on happiness and how it