The Raycasting Game Maker is a free easy to use game editor that creates simple raycasting games in the style of Wolf3D. The finished game needs only two files to run, an executable and a pak file with the game data. The game runs in Windowed- or Fullscreen Mode and supports 16 and 32 bit color.
Well, it's not so powerful engine, but if you got a real great imagination and your hands grows from right place - it's really great tool for creating old-fashioned games!