It is a windows program that uses DirectX. By default it plays the "Minestorm" game built into the rom, but you can override that by using "-c [catridge file]" when starting up the game. The default resolution is 330x410, but you can override that with "-x [xres] -y [yres]". Only single player mode is implemented. Use the arrow keys to control the direction. Keys 'a'/'s'/'d'/'f' correspond to buttons 1/2/3/4 on the Vectrex joystick. Escape quits the emulator.