This game seems to take its inspriation from a famous bar "somewhere in the South Atlantic". The morals of whether this should or should not be done are not for me to adjudicate on here.
The game has a static view of a bay surrounded by mountains. There are several ships moored in the bay (three to begin with) which have to be protected using anti-aircraft fire. The enemy's aircraft approach head-on, growing larger by the second and you, the anti-aircraft gun operator, have a cross-hair sight to help gun them down.
The aircraft come in waves - first ones, then twos and so on. Whilst reasonably easy to begin with, the game becomes more difficult with each wave. Whenever an aircraft gets through, the obvious (but not necessarily realistic) happens and a ship is bombed and disappears. If you shoot down enough of the aircraft, extra ships appear in the bay. When all the ships have gone the game ends.
The only distinguishable feature of this game is the effective 3D approach of the enemy aircraft. The static nature of the ships and the way that they appear and disappear shows no imagination on the part of the programmer.
Those of you with the First Byte joystick may use it with this game. Good luck to you. I hope you enjoy it more than I did.