Very nice work. I love the stained floor texture. Regarding lighting and light sources, it's hard to judge without seeing a couple examples. I don't think they are necessary for most maps, but they can add a lot to set a mood if done right.

Comments:
The stairs in the center of the map lack shading like the others, and though I think it originates from a level above, perhaps you could add some kind of shadow to indicate that.
The open room on the bottom right doesn't seem clear to me. The sections of solid ground appear to have a shadow around them to indicate they are raised above a lower floor (or is that water?). Anyway I think the shadow might be a bit too large and soft.