Stay Alive
This game here, intrigued me , I played it way into adulthood, against any poor unfortunate friend who expressed an interest in board games. It's still in my attic even today. It's a game of trap doors, strategy and marbles.
The idea was simple, keep your marbles safe and sink your opponents. Two layers on the board, the white and the orange and these were controlled by the levels round the board. But be warned when you think you are going to sink the opponents marble, the whole strip will move and you could end up sinking your own as well. Lots of tactics and a really nifty idea for a game.