Aliens have attacked the Earth and humans get world war III veteran major Stryker out of retirement to destroy Kretons stronghold to make attackers retreat.
In the game player controls Stryker's ship. At the beginning player chooses one planet from three planets where to go. Captured men can be saved by touching them. The things are indesructible which can protect enemies on the other side. Most power ups appear by destroying all enemies in formation. There are six levels for ship's weapon and power ups come constantly when not maxed. The first level fires single shot forward, second two shots forward, third 3 shots forward, fourth shoots three shots with one forward others forward diagonally, fifth adds back shot to fourth and last adds side shots to fifth. Weapon power up can be used as an additional shield because weapon reverts to single shot when hit instead of blowing up. Shields protect the ship. There are side shields which protects sides, rotating shield which protects from all sides and a round shield which shields from everything. The shields stand limited amount of hits before breaking. The ship has a screen clearing attack which is limited and can be collected by touching the appropriate power up. Other power ups are temporary and they include rapid fire, speed up and hover. They wear out with time. After every level game can be saved and the game shows ratio of kills and how many men were saved. The player also gets points depending on aforementioned ratios. Every third level is a boss level. In boss levels stryker must beat the boss to get to next level otherwise it is identical to normal levels except it has no captured men. After third level landscape changes and admiral talks to stryker.