You may find the Seven Pillars of Destiny interesting. These pillars are, in theory, an ever present guide for Bungie as they design and develop the game. I've highlighted the ones I think a apply here, but they are all good to keep in mind: Pillar 1: A World Players Want to Be In -- The most important stories we tell aren't going to be told by us. They're going to be told by players; their personal legends built from shared adventures. [b]Pillar 2: A Bunch of Fun Things to Do-- We want to put players in situations where they can feel successful, because being successful feels awesome. Whether you are a casual player or more intense, "Destiny" will meet you with something fun, no matter what your mood is.[/b] Pillar 3: Rewards Players Care About -- Everything you do in "Destiny" generates rewards like gear, weapons and outfits that can be customized. [b]Pillar 4: A New Experience Every Night -- Every time players sit down to play "Destiny," they experience something different. This pillar's goal led Bungie to create this diversity of activities -- an activity for every mood.[/b] Pillar 5: Shared With Other People -- Everything that is fun to do is more fun to do with your friends and when people are around you. "Destiny" is more fun with more people. Every activity can be played cooperatively. Solo is a totally valid way to play "Destiny," but you are constantly going to see other people in your game. Pillar 6: Enjoyable By All Skill Levels -- We want everybody who wants to play "Destiny" to be able to play "Destiny." All core activities can be enjoyed by novice players. Pillar 7: Enjoyable by the Impatient and Distracted -- Players don't want to read, and they don't want to go to the Internet to figure out our stuff. They want to be heroes and feel things they don't feel in their daily lives.