CHESS 64 VERSION 2.8C is a weak amateur game. Surprisingly it does have an opening book, but shortly after the opening the game deteriorates very quickly.
Entering moves on a PC are as follows: e2=e4 (use the equal sign, the screen will show a minus sign (-) since the game follows the Commodore 64 Keyboard.) For castling use the letter O ie. o=o or o=o=o.