One of the features of a megadungeon that I consider quite important is a large, sprawling first level so there is always stuff for new characters to explore. The megadungeon campaign is a campaign primarily centred around a single extensive dungeon. And may have many players and characters over the course of its existence.
— Merric Blackman (@MerricB) September 13, 2021
When the megadungeon doesn’t have a ‘safe’ place for first-level adventurers to explore (and you insist on starting characters at those levels), then you need to take the campaign outside the megadungeon each time new characters are introduced – which sort of defeats the point! Megadungeons are just one way of playing Dungeons & Dragons. I don't think I've ever featured an ENTIRE campaign around one, but several campaigns have featured them for significant parts of their runtime.
— Merric Blackman (@MerricB) September 13, 2021
To be fair, I like many of the levels below it to ALSO be big and sprawling.
But it's the first level that tends to be explored the most.
— Merric Blackman (@MerricB) September 13, 2021