Okinawa has already appeared as part of a games compilation from PSS, Conflicts 2, so putting it out by itself, even at so low a price, is a bit of a mystery.
This is the same "amphibious forces invade an island" format as the nearly identical Falklands '82 and Iwo Jima. Only this time the island is the gateway to Japan, Okinawa, captured by United States Marines and Army forces in April 1945. The player takes the American side against the computer, using a joystick to select simple options for his troops to land, move and fire against a virtually static enemy.
Like its cousin, Okinawa is for young children who like simple games with lots of sound effects and screens flashing, and aren't worried about the quality of the graphics. Anyone else will find it too simple-minded to give much enjoyment. And any serious wargamer who has met the earlier, related games would never buy it anyway.
PSS now put out such a wide range of wargames, including games which are a lot better than this.