Small thing I was playing with last month. No intentions to develop it into anything more, I just wanted to mess with the general feel (I make a lot of things like that). I've always been strangely fascinated with the pecularities of Wolfenstein 3D-like games, especially stuff like how you can't actually properly get right up to doors.
It was also a small experiment in map building, the map is built at runtime based on a slightly awful system where each character in a text file corresponds to a type of tile.
I probably won't return to it but it was novel to work on. Only thing I can think of in recent memory that hasn't used the base that I share between all my Unity projects.