- space. to move the ship in a circle... you know, just a starting point
that move ship in circle reminds me of a different arcade game from 80's
each stage you move around in a big circle close to borders of screen, shooting inwards in an invisible 3d tunnel, enemies appear prerendered 3d that reminds of spaceshuttles,moving outward from middle of screen and getting bigger/smaller
after clearing first stage computer takes control of your ship and a pic of Neptunus appear in fullsize onscreen and your ship enters Neptunus
and next stage gets started
its all repeated with Uranus,Saturnus,Jupiter,Mars and Earth,inbetween each has a enemy stage to fight thru,it makes use of a classic music piece