Changes from the arcade
- Two different control schemes are offered, as explained above. One operates like the arcade, allowing you to choose what side of the screen to travel to, and the other instructs the ship to travel clockwise or counter-clockwise.
- In addition to the single shot gun, which can be upgraded to a double shot gun, there is also a powerful energy blast weapon which has limited ammo, and will destroy everything in its path, excluding certain bosses. Up to seven such shots can be stored by the player.
- In addition to a weapon upgrade pod, other bonuses may appear between the space stations, including extra energy blast shots, a crash bomb which destroys every enemy not currently in the center of the screen, or an extra life. More than one set of space stations may appear within a single stage.
- More planets are visited during the game, including Pluto, Venus, and Mercury, and then on to the Sun. Bonus rounds count as a stage, and there is a total of 40 unique stages before the game starts over from stage 1.
- Aside from the regular enemy space ships, there are a few enemies which only appear en route to particular planets. Some of these enemies are unique to one planet, and others reappear during warps to subsequent planets.
- The second warp to each planet involves the destruction of four enemy pods which rotate around the center of the screen, instead of clearing all of the enemies which occupy the center. The music for such stages is also unique.
- Bonus stages include alternately colored enemies which release some kind of power-up or bonus when destroyed. These include escalating points which culminate in an extra life, or extra energy blast shots. These bonuses will always appear on the direct opposite side of the screen from the player.
- For the Famicom Disk version, there is a more detailed story. It is shown as follows:
- "It is the 26th century, and the earth federal government starts to build military forces covering the whole solar system. People are forced to work without rest."
- "By the time of 2545, Domes, the dictator of earth federation, launches a command of total invasion to outside the solar system. Since then, people are wrapped in fear."
- "At the same time outside the solar system, Rudolf, leader of the resistance force, the person who was exiled by trying to murder his father Domes 10 years ago, has ended his exile and returned with Gyruss the space defender force."
- "Can Rudolf stop Domes and put an end to the chaos of solar system?"
The game flow for the NES and Famicom Disk System version of Gyruss is very similar to the arcade's. Every planet takes three warps, including Neptune (which still takes place first, before Pluto.) Each of the three warps has a particular pattern to it, as explained below.
- Three warps away
- The first warp to a planet is not very distinct from a typical warp in the arcade version. Waves of enemies fly onto the screen in particular formations before settling into position in the center of the screen. A few planet specific enemies may appear, but not many.
- Two warps away
- The second warp to a planet is extremely different, and features a new element in the game: enemy pods. Four pods rotate around the center of the screen. These pods take several hits to destroy, and the stage is not complete until all four pods are destroyed. Even though enemies fly onto the screen in the usual formation, the number that actually make it to the center is irrelevant, since the pods will continue to release enemies for as long as they are around. More planet specific enemies will appear throughout the stage.
- One warp away
- The third and final warp to a planet starts out identically to the first warp: waves of enemies fly onto the screen in formation, and settle in the center. However, once all of the enemies are defeated, the player is presented with a boss battle that must be cleared in order to advance to the planet, and to the chance stage beyond.
- Unique enemy
- Just as in the arcade, indestructible asteroids are flung out from the center of the screen in the direction of your ship. Unlike in the arcade game, they don't wait for the second stage before they start to appear. No amount of shooting will destroy them, so you better move out of their way. Although you can destroy them with an energy blast, it is better not to waste these powerful shots on asteroids.
- This is first of the most common type of boss that you will encounter throughout your journey through the Solar System; a station outfitted with pods. Each pod is invulnerable to attack when closed, and only opens briefly in order to launch an attack on your ship. In the case of this boss, all four pods fire a spread of three bullets at you. You must position yourself in front of one of the pods before it opens, and shoot it as rapidly as you can until you are forced to move out of the way of the shots it fired at you. It is a good strategy to remain focused on one pod and destroy it before moving on to another; as more pods are destroyed, the remaining pods open more frequently, thus exposing them to your attack sooner. While an energy blast can knock a pod out extremely quickly, you should not use them against this boss in order to save your ammunition for tougher foes.
- Unique enemy
- While it's theorized that very little can survive in the cold vacuum of space, these amoebas seem to feel right at home. There are two different kinds of amoebas that threaten you here, both visually indistinguishable. The more common kind flies back and forth as it comes closer to you. Each shot knocks it back to the center of the screen briefly before resuming its pursuit of you. The second kind flies straight in one direction. When you shoot it once, it will split into two. These two amoebas will split once more when shot, but after that, further shots will destroy the four resulting amoebas.
- The boss before Pluto consists of two parts. The first part is indestructible, and spawns the second part: a wriggling mass of orbs that shift back and forth randomly. The indestructible orb stays on the outside circle at the same level as you, slowly pursuing you. The wriggling mass on the other hand moves in a fashion that is very hard to predict. It spreads out and contracts, moving both closer to and farther away from your ship. To defeat the boss, you must shoot every segment of the mass until all of its protection is removed. Every time you successfully shoot a segment, the protection breaks off and flies toward your ship, forcing you to dodge the debris. While shooting at the mass, make sure that you move continuously in order to avoid getting struck. Naturally, you must avoid getting too close to the orb the entire time.
- Unique enemy
- What starts out as a very calm orderly enemy turns into an unpredictable threat with a single shot. These enemies start out in their shell and slowly spiral out from the center of the screen. If they are shot, their shell is destroyed, and the revealed creature begins moving very frantically back and forth as it moves in and out of the screen. Be sure to get out of its way when it's approach the edge of the screen, as its movements are so erratic, you are likely to get hit without much warning. Try to shoot it as its moving back toward the center.
- As you get closer to completing your warp, a second and more rare unique enemy begins to appear. Four orbs appear from the center of the screen and snake back and forth as they approach the outer edge. When they reach the edge, they begin to return to the center, and repeat the process until they are destroyed. You must shoot it enough to destroy all of the orbs before the threat is eliminated.
- Much like the boss before Neptune, this boss is a station with four pods on the exterior. These pods are arranged diagonally, and they fire a different weapon as well. Each of the pods releases homing mines that slowly drift in your ships direction as they get closer. While they are very much a threat, they can be destroyed with enough shots. That's both good and bad in this case, since while you can remove them, they have a tendency to absorb shots which you intended for the pods themselves. As you reduce the station to two, and ultimately one pod, the mines will come out so frequently that it becomes harder to get a clean shot at the remaining pods. If you have energy blasts to spare, you may want to consider using one against the final pod, and even against the second to last pod if you have close to seven blasts in store.
- Unique enemy
- The unique enemy on the path to Saturn resembles a mechanical jellyfish. Only this jellyfish is wearing armor that protects most of it from basic attack. The only portion of the jellyfish which is exposed are the tentacles. As it flies out from the center of the screen, its in a constant rotation, so the tentacles are only briefly oriented in the direction of your guns. You must time your shot very carefully to remove this threat from the screen, or quickly move out of its way entirely.
- Adding a bit more complexity to the previous station bosses that you've faced so far, this station has six orbs, three on the top and three on the bottom. Each set of three pods fires a different weapon. The pods on the top and bottom employs a particularly annoying weapon: a large indestructible orb which tries to lock onto your position, and completely blocks all shots fired by your main weapon. Once it locks onto you, it proceeds to fly straight to the edge of the screen and you can fly out of its way. It would be best to remove these two pods before any of the others since their tendency to block your shots makes progress particularly difficult. It may be wise to use an energy blast or two on the center turrets, as you will almost certainly have a full stock at this time, and will get them back before the next boss. The remaining pods shoot heat-seeking mines and a spread of three bullets, making them a bit easier to destroy.
- Unique enemy
- The path to Jupiter contains an unusual amount of space debris. Plates from some destroyed vessel fly out from the center of the screen toward your ship. Like asteroids (which also appear on the way to Jupiter), plates cannot be destroyed. Unlike asteroids, when you shoot a plate, it breaks apart into four indestructible pieces. These pieces will not break up and further, but the amount they spread apart prevents you from firing past them until they clear the edge of the screen.
- A nearby creature has gathered up all of the plates it could find in an effort to construct makeshift armor for itself. In the first phase of this fight, you'll have to shoot the boss in order remove all of the armor. As you do, pieces of the armor fly off, both of their own accord, and particularly when you destroy a segment of the armor. You must move continuously in order to avoid being struck by the pieces which break off. Once all of the armor is removed, the boss reveals itself to be a tentacled monster, possibly inspired by one of the bosses in Gradius. Once the tentacles appear, they flail back and forth, capable of striking you ship if you are directly in front of the boss. Not even a blast shot can penetrate the tentacles, so use only normal shots. In order to survive, you must avoid being in front of the boss at all costs. Move continuously in a circle, always remaining just outside of the tentacles reach. Fire constantly at the boss, and if you are just the right distance ahead of the boss, it will move into all of your shots until it is destroyed.
- Unique enemy
- The first unique enemy on the path to Mars actually originates from the arcade game. The two satellites that spread out from the center, bouncing a high energy beam back and forth between them finally appears at this point in the game. Unlike the arcade, the beam does not appear to stop bouncing once you destroy one of the satellites. It will only complete disappear once both satellites have been destroyed, but due to the speed that they move at, this can be difficult to accomplish.
- The second unique enemy is truly new. Cannons warp into position out of nowhere, and once they stop blinking, they fire a blast at you before beginning to warp back out. They are only vulnerable when they are solidly in place and no longer blinking. However, you'll only have a brief amount of time to shoot at them before you have to get out of the way of their shot.
- The boss before Mars is another station, with eight pods positioned all the way around. There are two different types. The pods on the diagonals shoot a spread of three shots. The other four fire two orbs which spread outward around the edge of the screen to nearly 90 degrees around. These orbs can be destroyed by shooting them with enough shots, but this is only really possible if you are directly in front of the pod when they appear. Otherwise, the risk to you ship is too great. Those pods which shoot these orbs should be your highest priority, as the spread shot pods pose a smaller threat. If you have saved up enough blast shots, you should consider using at least one, possibly two. By firing at the right angle, you can actually destroy two pods at a time. So with two shots, it's possible to destroy four of the pods.
- Unique enemy
- In addition to asteroids and fracturing plates, a new unique enemy appears on your warps to Earth. This armored enemy spins out from the center and tries to line up with your ship before stopping, and exposing its armature in order to fire at you. It is only at this time that you can fire at it and destroy it. Wait until there are no other distractions before you focus on it, and wait for it to arrive in front of you, then blast it and move out of the way in case it fired.
- Guarding the passage to Earth are three ships that are not too disimilar from your own. They all fly at the same distance from the center. Each ship is a different color and has a different weapon. The blue ship is the only ship which moves quickly, and it stops randomly to fire a single large orb. The orange ship moves slower than the blue ship, and it fires a double shot similar to your upgraded guns. The pink ship moves around the same speed as the orange ship, and it continuously fires a stream of heat seeking mines. There is no urgency to destroy one ship before any of the others, and you should opportunistically attack any ship that is conveniently in front of you until all of the ships are removed. None of the ships are so powerful that you need to worry, as long as you continue to move out of the way of the mines as they approach you, and don't move into the path of any other ships' shots.
- Unique enemy
- In addition to satellites and cannons, which appear during this portion of the journey, the regular jets are joined by a particular type of robot. This robot travels out from the center and deposits three bombs around the edge before returning to the center. After a period of time, the bombs detonate, and you must avoid the resulting explosions. The robot is easily destroyed with a well timed shot, but once it's on the outer edge depositing bombs, you'll have to steer clear of it until it starts making its way back.
- You're back to fighting a station with eight pods, just like before the warp to Mars. However, the pods in this particular station have all four varieties of weapons that you've faced before; The three spread shots, heat seeking mines, the two orbs which spread out along the edge, and the blocking shot which tries to position itself in front of you. Of the four weapons, the later two are more difficult to deal with then the former. Fortunately, pods which produce these two weapons are neighbors, so one well placed energy blast can remove two such pods, and a second blast will remove the remainder. Then you can focus your attack on the remaining four pods which should prove much easier to destroy.
- Unique enemy
- One unique enemy that you'll encounter is the four orb snake-like enemy which you originally encountered infrequently on the way to Uranus. Now they'll appear quite steadily, forcing you to deal with them as you take out the other enemies. The other are huge chunks of crystal which arc toward you. If you shoot them, they break apart into four pieces (just like the plates of metal), and at least one piece will continue to arc in your ship's direction. You can, however, destroy the chunks if you shoot them enough times.
- The boss of this stage is a giant brain encased in orb. The orb is locked by eight small pods. Each pod is guarded by a rock. The rocks fly out toward your ship when you fly in front of them. In fact, they will hook left or right in an effort to reach you. You'll have to shoot around the rocks to remove the pods. Fortunately, as long as you keep going the same direction, they will all veer the same way, so you can circle around, stopping to fire a few shots at each spot, and then moving on. Alternatively you can destroy the rocks by shooting them with an energy blast. You should use at least one in order to give yourself a safe position on the screen where you don't have to worry as much about getting struck by the rocks. For the remainder, you'll have to lure the rocks away from the pods and shoot the pods as quickly as you can before the rocks return in place. Once all the pods are removed, the case cracks open, and the resulting shards that fly outward can destroy your ship. Any remaining rocks stay in place, while the exposed brain shoots lightning around in random directions. Shoot the brain as fast you can to avoid taking any unnecessary risks by sticking around for too long. If a rock or lightning bolt gets in your way, simply use a blast. No more than two should be needed.
- Unique enemy
- On the way to the sun, the only unique enemy that you'll encounter are blazing fireballs. They travel quickly from the center of the screen, and arc in your direction whenever they are close. They are indestructible, so your only option is to avoid them. When you are only one warp away from the sun, you'll encounter a stage where no enemies appear, and you are instead assaulted by nothing by wave after wave of fireballs. Do your best to survive the barrage in order to reach the boss.
- The battle starts out as a sun launching fireballs at you, which you can destroy. Focus your attacks on the sun itself. After you shoot the sun enough, it explodes in a ring of fireballs which you must be sure to avoid. The boss in the middle of the screen launches small eyeballs outward, which can be destroyed with enough shots. They float out and stop at the edge before moving on. The boss is only vulnerable to attack when eye is open. As it takes more damage, the eye begins shooting laser beams at your ship. The eyes appear in a predictable pattern, and there is a strategy that you can exploit to survive the battle. Stay on the bottom of the screen, and shoot the first eyeball that travels straight down. Then move slightly to the left and shoot the next two eyeballs which descend from that angle. Come back to the right, start firing up at the eye. Avoid laser by edging to the left, where you will destroy another eye which is about to arrive at the edge. Repeat this pattern to wear down the boss gradually. As it gets closer to defeat, it will turn pink. Once you destroy it, you will win the game and be shown an ending screen before the game starts over at a higher degree of difficulty.