You play two black bishops against eight white pawns, and nothing else. Some teachers call this game Bishops Rule. White moves first and wins by getting one pawn to your side of the board. You win by capturing all eight pawns, or by leaving White with no pawn that can move.
This is the game for learning how a bishop really works. Each bishop lives on one colour of square, so the two have to work as a team, and a bishop far away can still guard a whole diagonal. Be careful, though: a pawn can capture a bishop that stands diagonally in front of it.
There is no en passant in this game. Three difficulty levels change how far ahead the pawns look, and on easy they often play a bad move on purpose so a beginner can win. Want to be the pawns instead? Try Pawns vs 2 Bishops.