3-Demon was published by John D. Price and PC Research Inc in 1983. It is basically a Pac-Man game, but presented in a 3D way.
It is quite a major deed for the developer as it uses only the CGA graphics to create a believeable 3D maze.
Like Pac-Man, our objective is to collect all the dots on the ground while avoiding to be eaten by the ghosts wondering around.
There are power-ups for us to pick up too. After picking up the power-up, we can eat the ghosts instead.
Not a bad game to spend a few minutes on. You can download 3-Demon here.