Those pics look nice already Just remember that corridors are usually not good for the flow, so it would be nice to see some shortcuts or other doors in those hallways. Btw I have some pictures of real "gothic" architecture for you(just think of old churches like the Notre Dame or whatever
structure of gothic windows (I'm sure you can make sth. great out of it
But if you want to make a dark, "goth"- map, you could call it something like "medieval crypt", or just "crypt" or whatever...
Or call it "stevie's tomb"