It contains what it says on the tin, an old style blue map, a parchment style map and a pdf with tables.
The edges of the dungeon match up with the previous installment for those of us who want a humongous map. The map is mostly 2D with some possiblities (portals and other indeterminate symbols) to get from one side of the map to the other. There are caverns, regular rooms (some unreachable) and even some tentacles. No pirates or ninjas though.
The parchment version is beautiful and a good source for handouts to players (possibly torn up in pieces).
The blue map is a bit more plain which is good as the DM will want to add his/her own annotations/legend.
The pdf is simply a collection of useful tables which should provide you inspiration. As this map has no official theme or associated adventure you will need to put in some work, but considering its size (and depending a bit on how many surprises you sprinkle around) your friends should get at leasts several nights of enjoyment out of this one.
[5 of 5 Stars!]