This is a C# port of OneLoneCoder's CommandLineFPS, which is originally written in C++.
A First Person Shooter at the command line? Yup...
This program expects the console dimensions to be set to 120 Columns by 40 Rows. I recommend a small font "Consolas" at size 16. You can do this by running the program, and right clicking on the console title bar, and specifying the properties. You can also choose to default to them in the future.
This is designed for MS Windows