Star Jacker is a vertically scrolling shoot 'em up where the player controls a Universe Squadron whose job is to attack various enemy space colonies while evading or destroying the enemies UFO forces before returning to the Star Jacker mother ship. The main difference from other shooters is that the player here controls three space ships at once. As the front ship move the others follow its trail. This means that the player can shoot three shots at a time but it also means that enemy projectiles are harder to avoid since the ships take more space. However if hit the size of the squadron will decrease. The player has two means of attack: a regular fire for shooting down UFOs and a bomb attack for taking out ground targets.

If a high score is attained a mystery target will appear. By destroying this the squadron will warp to the mother ship. The player will then be granted one extra ship and then game will continue. The game goes on until all ships in the squadron have been lost.

The SG-1000 and SG-3000 versions differ in that the player there starts out with four ships and not three.