Anatomy of an Achievement

Whether they annoy you or fulfill your nerdy collection habit, achievements have spread across the gaming landscape and are here to stay. The Xbox Engineering blog recently posted a glimpse into the creation of the Xbox 360 achievement system, discussing how achievements work at a software level, and even showing a brief snippet of code. They also mention some of the decisions they struggled with while creating them:
"We are proud of the consistency you find across all games. You have one friends list, every game supports voice chat, etc. But we also like to give game designers room to come up with new and interesting ways to entertain. That trade-off was at the heart of the original decision we made to not give any indication that a new achievement had been awarded. Some people argued that gamers wouldn't want toast popping up in the heat of battle and that game designers would want to use their own visual style to present achievements. Others argued for consistency and for reducing the work required of game developers. In the end we added the notification popup and its happy beep, which turned out to be the right decision, but for a long time it was anything but obvious."

http://games.slashdot.org/story/10/0...an-Achievement