I have been working on a new megadungeon, Monster Hill. It is the name given by locals to a hill of ill reputation that spews out terrible monsters and is a haven for goblins and bandits and other neer-do-wells. It has in the past been know as a home to demon worshipers, who are supposed to have constructed the complex long ago. Rumors state that there are portals to the infernal realms in the depths.
I'm running this so that many groups can enter and leave they're mark on the complex. Theoretically I could play it for years for many different groups, and any changes the PCs make would remain. Also I'm going to be going with an approach similar to what