Dungeons in ToM consist of several layers utilizing full 3D space, each layer constructed from tiles. Layers can span to several thousand or more tiles in width. The maximum size is currently unknown. Layers can also be stacked in the same manner, with the limit being around several thousand stacks, but it's more likely that the average dungeon will have a more realistic number of layers.
The game will progressively get harder the deeper you go and the dungeon environment will change. You will be given the option of using bind points to respawn at so that you don't have to find your way through a maze to get back to where you were. Bind points may not be permanent, and they may have to be maintained somehow.
Dungeon walls can be destroyed by use of explosives, spells, or wall pounding AI. Paths can be carved through dirt and rock for the purpose of creating shortcuts, hiding places, mining, reconstruction, or just for fun.