The player's plane is equipped with machine guns and torpedoes and ammunition is unlimited. The colour of the sky changes according to the time of the day (afternoon, evening, night). F6F Hellcats are common enemy fighter planes the player will encounter. Occasionally, the player would run into a B-24 Liberator and has to shoot each of its four propellers before the B-24 flies away. Sometimes when player has shot down a number of B-24s, he or she would encounter a falling satellite across the screen. A high amount of points would be rewarded if the satellite gets destroyed.
Enemy resistance comes not only from the air, but from land and sea as well. Sometimes, an American naval destroyer or submarine would try to down the player's plane with AA fire. Aircraft carriers can sometimes be seen in the distant horizon (but can still be sunk with torpedoes). At the end of a stage, the player faces a mobile shore battery on an island. This battery must be destroyed in order to complete the mission.
Source: Wikipedia, "Sky Destroyer", available under the CC-BY-SA License.