Diablo 3 is going to introduce a new element of game play called the “adventure system”. This new system will incorporate randomly generated bits of landscape and quests to incorporate into the zones.
As in Diablo and Diablo II, Diablo III will have zones which have static exterior borders, roads and towns. Maintaining static borders is important because it allows players to easily and properly navigate through the different zones. If the borders weren’t static, then you wouldn’t know where the hell you were going half the time. A bulk of the terrain and content in between the borders will be static as well.
What’s changing, is that in between these static areas and borders, Blizzard has created specific “cut out” sections of the map which will provide randomly generated content. Each area will have several pieces of content which the game can randomly choose from. These randomly generated bits can simply be different scenery or they may have added features such as quests, little events or even mini-bosses. These randomly generated pieces of content are intended to keep things fresh and interesting, even though the bulk of the map will remain unchanged. This will greatly enhance the re-playability of the game.
The Diablo 3 dungeons will also incorporate the new adventure system. While navigating through the randomly generated dungeon layout, you’ll also be able to happen upon random quests and events as well. Sounds exciting.