Cliff Hanger was one of Airfix's "Carry Case" games, intended to be portable fun!
In this game, players place protruding pegs through a wall set between them, and then hang their men from the pegs, so they cannot see each others pieces.
They then take turns to remove a peg, hoping to dislodge their opponent's men, while retaining theirs. The player with the most men still hanging when there is only one peg remaining wins!