Thought I might add the walls and see how that looks.
It looks okay, but a bit tame. It lacks light and shadow. But that will require me to refactor some parts of my small engine. At the moment my render loop calls the map's render function. That needs changing so that my render extracts information from the map and renders it. Right now, it would be impossible to add the player or monsters unless the map knows all about them, and I don't like my objects knowing to much about each other.
The map looks very compact, so some sort of fog of war might have to be implemented. Adding light might solve it as some parts of the map would be darker that others.
The tiles I am using have been drawn by a friend of mine. I hope I can convince him to create some more stuff for my small game.