Keys "s"=save "l"=load "b"=back once
1960's. Pawns capturing become knights. Knights capturing become bishops. Bishops capturing become rooks. Rooks capturing become queens. Queens capturing leave behind a friendly pawn. Kings capturing leave behind a friendly copy of the unit captured. Pawns promote only to bishops.
These are simple illustrations rather than strong opponents.
Bug reports? -- Thank you! Keep them coming!