I think you'll have to work a lot on your lighting to really pull it off here, having the map as dark as it is and then adding point_spotlights gives you really weird contrasts. Using the godrays indoors is always chancy at best.
The architecture itself looks great, you have some clever solutions to pull the theme off but adding props and lighting needs some more hours. I think you just need some colors somewhere to get rid of all the brick/brown textures everywhere. I'm not sure of how your upstairs areas look but if everything is the same red-brownish colors, finding your way around could even be harder because everything looks too much alike.