It gets awfully lonely sitting on your own in a bunker until the enemy decides to drop in! 'Your bunker' is in fact a field gun which you control, sitting in the bottom centre of the screen. Above you, in the sky, helicopters stream by in both directions, spewing paratroopers out on top of you. Their object is to get three men safely on the ground, at which point they stride off and return in a large tank against which you are defenceless (and dead!) and that's that. Your aim is to prevent them from landing any men and you score for paratroopers destroyed and helicopters knocked out.
The game continues on after loss of life, resetting the score to zero, quite automatically.