I like the tiles, very evocative.

The only thing that bugs me (and this is me mind you, so take it with a grain of salt), if the majority of corridors are only 5' wide. This means, for a game like D&D, where each creature occupies a 5x5 square during combat, the fights will become a battle of the front rank between the PCs and the Monsters. Further, Large Monsters (2x2 squares) are even further hampered by needing to squeeze in combat, a major penalty to those of the LARGE size.