Assault On Port Stanley takes place during the Falkland Wars and the player takes the role of an S.A.S. commander and has to liberate Port Stanley from the Argentinian occupants. The task at hand is to break through the enemy blockade and pick up troops from a sabotage mission behind enemy lines.

The game is split into three stages. The game starts with the player being aboard a warship that is slowly approaching land. This section works similarly to the battle station sequence of Beach-Head. The player takes control of the ship's cannon from a first person perspective and has to shot down the enemy ships as they appear while at the same time avoiding their fire. At any time the player can take off with his helicopter and move on to the next stage which is a shoot 'em up game in the style of 1942. However the helicopter has a limited amount of fuel and therefore the player can't launch it too early, as it won't be enough to reach the shore. The number of waves of enemy planes in this section depends on how many ships the player has destroyed in the naval stage. Upon reaching the island the third stage is launched which plays like River Raid. The player flies his helicopter over a channel while trying to avoid the cliffs on the sides and the enemy boats and barrages. Along the banks there will be stations where the player can land to pick up men and refuel. At the end of the level the player gets bonus points for each man that has been rescued.