Gyruss

The entire solar system is being attacked by the vicious Gyrusians, and it's up to you to save the day! You will need to fly your spaceship to each of the nine planets and then clear three stages of enemies to rid that planet of the Gyrusians. You start the game with a single cannon, but can gain a double cannon after shooting a power up satellite. After clearing each planet, there is another bonus stage where additional weapons and bonus points can be collected. Gyruss is an arcade action shooter, however instead of piloting your spaceship horizontally or vertically, you move in a circle around the perimeter of the screen. The NES version of Gyruss adds to the original arcade version additional music, additional weapons, new enemies, and a large boss at the end of each level. The gameplay is similar to that of Galaga but presented in a forced 3D perspective, with the player's ship facing 'into' the screen and able to move around the perimeter of an implicit circle. The scrolling starfield of earlier space shooter games is arranged to fit the 3D perspective, with the stars coming into view at the centre of the screen and flying outward, giving the impression of the player's ship moving through space.