Here’s an interesting article on Gamasutra about Achievements that I think is a must-read for game designers:

Achievement Design 101

Every game on the Xbox 360 (with the exception of Xbox LIVE Indie Games) ships with achievements and games have used this functionality in many ways to both their benefit and their detriment. For example, Avatar The Last Airbender is known for allowing you to add 1000 points to your total gamerscore within a couple of minutes while Guitar Hero has its ’hardest-song-on-expert’ achievements like Through the Fire and Flames, in which most people have trouble getting past the first 2 seconds of the song. Achievements have added an interesting dynamic to games and now many other games like World of Warcraft have adopted a quantifiable scoring system along with Sony’s Playstation 3 Trophy system and Steam’s PC game achievements. For some, it’s even been a reason to purchase a game for a specific platform over another.

And while for the most part, the achievement system has been considered mostly local to each game but there is also something to be said for the achievements ecosystem like on Xbox LIVE where players can compete amongst themselves for the highest total gamerscore across all of the games played, which means games that are too easy to ‘finish’ like Avatar or games that can be exploited with cheats can be harmful to the ecosystem and devalue the scoring system. In this sense, it is ideal to have each and every game find a good balance in their achievements ranging from easy to hard and finally to the hardcore, awarding players for their level of investment into the game. Paired with in-game rewards that open up new gameplay for the player, achievements can go a long way to help an individual game retain replay value while keeping the achievement ecosystem healthy.

So next time you’re thinking about how to get players to continue playing your game, consider having a good achievements system (especially if you’re making commercial games!).