While it enjoyed a fair amount of success at the arcades, many people remember Gyruss for it's Music. Never before have space shoot 'em ups and classical music gone together so well. While many people can still hum that catchy little tune to this day, most don't know that it's actually Bach's Tocatta and Fugue in D Minor. In the arcades Gyruss was able to produce an absolutely amazing rendition of this classic tune using five (count 'em) five sound chips! Needless to say it was a long time before something like this was ever tried again, but in the case of Gyruss, the results were incredible.
Gyruss can best be described as a cross between Galaga and Tempest. The player must shoot large formations of enemy ships (just like in Galaga) that come out from the middle of the screen while moving around the outer edge in a circular motion (just like Tempest). Your goal is to reach earth by warping through waves of enemy fighters (each stage is called a warp). Of course you can't just make a straight beeline for Earth, no that would be too easy, instead to get to Earth you must start at Pluto and make your way through several planets (Neptune, Uranus, Saturn, Jupiter, and Mars to be exact). Successfully making it to a planet will reward you with a bonus stage that seems all too similar to Galaga.
Gyruss is interesting in that that actually rewards you for not being perfect. For you see if you constantly destroy all the enemy ships in a formation as the approach then you'll never see the satellites. Satellites only appear when at least three enemy ships are in the center of the screen, and that only happens if you let a few sneak by at the beginning of the stage. Shooting the center satellite of the group will reward you with double shots, which makes the game a whole lot easier.
While most of the elements of the arcade game made it into the 2600 version (such as the indestructible meteors), one enemy that got left out was the force field generator. In the arcade these creatures would appear in pairs generating an indestructible force field between them! If your ship ran into them you'd loose a life, and the only way to shut the force field down was to destroy one of the generator ships. These annoying little ships made the later levels much more difficult, and without them the game difficulty never gets quite high enough to be truly challenging. Why they were left out is anybody's guess, but it may have been too difficult to implement on the 2600.
Overall the 2600 version of Gyruss is an amazing port. The only major thing missing (other than the afore mentioned force fields) are sound effects. In order to get the amazing music on the 2600, Joe had to lose all the sound effects (having in-game music in a 2600 at all is quite rare). While you think that this would be distracting, it's actually quite nice as the music never gets interrupted with game sounds. Other than having a slight graphical downgrade, the 2600 version of Gyruss stacks up quite well with versions appearing on more powerful consoles.