Steel Gunner/Gameplay

Controls

 * Lightgun: Use the lightgun to move the gunsight of Garcia (or Cliff if you're player 2) around the screen. Squeeze the trigger to fire your character's machine gun, and press the button on the side to make your character launch a missile, which will injure (or kill) all enemies currently on the screen.
 * 1 or 2 Player Buttons: Push these buttons to begin the game as player 1 or player 2.

Garcia and Cliff
These Neo Arc police officers are the protagonists of the game; they are on a mission to save the well-known authority on physics, Dr. Ryan, and his assistant, Dr. Ellis, from the radical terrorist army known as STURM (but it is not known what the letters stand for). They must progress along a predefined path through each of the game's four acts and possess the power to shoot anything on the screen including the background objects and innocent bystanders - but just like how they will lose energy, if they should get shot by any of the enemies, they will also lose energy if they accidentally shoot a bystander (that is also indicated by the bystanders collapsing and shouting "Ouch!" or something similar). When they are low on energy, the text "WARNING" will appear over their life bar, and a warning sound effect will start to be heard from the C140; however, they will regain energy (and gain additional missiles, as they only start out with four) at the end of all except the final act, depending on how accurate their shooting was.

Innocent Bystanders
There are ten different types of innocent bystanders to watch out for; whenever one runs into view, the text of "DON'T SHOOT!" will appear above them. If you accidentally shoot one, you will lose some of your energy as if you had been hit by an enemy (again, it will also be indicated by them collapsing and shouting "Ouch!" or something similar) - and this means that if you accidentally shoot one of them while you are low on energy, it could end up costing you the game. However, they are all smaller than the enemies, so should be easy to avoid.

Kobolt
These Transformer-like robots attack by either: running into view from the left or right sides of the screen, coming up directly in front of you, jumping back into view from directly in front of you, or jumping out from behind background objects while firing shots (or throwing grenades) at you.

Domu
These Transformer-like robots attack by either coming up from behind the background objects or running into view from the left or right sides of the screen while firing missiles at you; they take more hits to defeat than the Zaku, and will sometimes cause a huge explosion upon death.

Frogger
These shield-holding Transformer-like robots will attack by jumping out from behind the background objects and throwing more grenades at you; once you have fired enough shots at their aforementioned shields to destroy them, you will have to fire enough shots at the Gufu themselves to kill them.

Harpy
These airborne Transformer-like robots will attack by flying into view from the left or right sides of the screen while firing missiles at you; five of them also appear at the start of the game, to kill the three airport guards who are escorting Dr. Ryan and Dr. Ellis into view.

Biker Zaku
These hoverbike-riding Transformer-like robots will attack by flying out from behind background objects or flying into view from the left or right sides of the screen, while firing shots or throwing grenades at you; they take more hits to kill than the normal Zaku, and will fall to the ground.

Mosquitoes
These one-eyed, three-legged, airborne robots will attack by flying into view from the left or right sides of the screen while firing shots at you.

Green Falcon
This enormous green aeroplane is the first boss of the first act; once the screen has stopped scrolling inward, it will fly towards you while firing missiles at you. Once you fire enough shots at it to defeat it, it will fall to the ground as Hart emerges from its wreckage.

Flamer
This enormous red Transformer-like robot is the second boss of that first act; once he has emerged from Green Falcon's wreckage, he will start shooting flames at you. Once you have fired enough shots at him to defeat him, the text "ACT 1 IS OVER" will appear upon the screen and the "act clear" theme will be heard from the Yamaha YM-2151 for the first time, as four Neo Arc police cars draw up on both the left and right sides of the screen.

Stalker
These four-legged, one-eyed, arachnid-like robots attack by running into view on the ground or ceiling from the left and right sides of the screen or emerging from pairs of double doors in the background while firing shots at you; they can also jump to the ceiling or drop to the ground.

Raven
This enormous, red, airborne Transformer-like robot (who looks like a much tougher version of a Mobile Armour), is the boss of the second act; once the screen has scrolled inward past the Micro Fusion Engine, he will fly into view from the left side of the screen. Four red fast-forward signs will then appear on the right side of the screen, as it scrolls to the right after him and he starts firing missiles at you - and once you've fired enough shots at him to defeat him, he will explode and fall to the ground. The text of "ACT 2 IS OVER" will then appear on the screen as the "act clear" theme is heard from the Yamaha YM-2151 for the second time; however, because the act ends underground, no Neo Arc police cars will draw into view this time. (There are versions of the game that has the Neo Arc police show up after Raven is destroyed.)

Pods
These airborne gun-like robots attack by flying into view from the left or right sides of the screen while firing shots at you, like the Mosquitoes.

Enormous Cannons
These enormous automatic heavy guns (which are found mounted on top of boats) attack by turning to face you, and fire shots at you.

Missile Guns
These (not-quite-so-enormous) cannons attack by coming up into view on top of the boats that are in the background and fire missiles at you.

Beam Guns
These other not-quite-so-enormous cannons will (for the first and second types) attack by coming up into view on top of the boats that are in the background to fire shots at you, and (for the third type) having shutters in the sides slide up to reveal them, and fire shots at you.

Centaur
This enormous red-and-black robot is the boss of the third act; as four more red rewind signs appear on the left side of the screen (and it starts scrolling to the left), he'll hover into view from that side while firing missiles at you. Once you have fired enough shots at him to defeat him, he'll explode and fall to the ground - and the text "ACT 3 IS OVER" will then appear on the screen as the "act clear" theme is heard from the Yamaha YM-2151 for what is a third, penultimate time and four more Neo Arc police cars draw up on both the left and right sides of the screen.

Green Centaur
This enormous green-and-black version of the above robot is the first boss of the fourth act; as the screen stops scrolling inward, he will hover into view from the left side of it, while firing missiles at you. Once you have fired enough shots at him to defeat him, he will explode and fall to the ground - and the screen will then continue scrolling inward, as there are still two more bosses to go before the act is over.

Enormous Weapon Ryushiferu
This enormous one-eyed robot is the second boss of the fourth act; as the screen stops scrolling upward and you come face-to-face with him, his own unique theme will start to be heard from the Yamaha YM-2151 as he starts firing missiles at you. Once you have fired enough shots at him to defeat him, he will explode - and the screen will then continue scrolling downward, as there's still one more boss to go.

Gatse Bernar
This android is the third and final boss of that fourth act; as the screen stops scrolling inward again, his own unique theme will start to be heard from the Yamaha YM-2151 as he comes up from the bottom of the screen and starts firing shots at you. As you are firing shots at him (they will not register while he is holding his right arm in front of his face to block them), his "flesh" covering will wear away, and expose his metallic body (as you can see in the image to the left) - and even though Dr. Ryan and Dr. Ellis are also present in the background, you fortunately cannot shoot them. Once you have fired enough shots at him to defeat him, he will explode, and sink back down off the bottom of the screen; the text "ACT 4 IS OVER" will then appear on the screen as the "act clear" theme is heard from the Yamaha YM-2151 for the fourth and final time. You can now sit back and enjoy the ending, which states that the terrorist plot was stopped, and Drs. Ryan and Ellis had been safely rescued as they run up to Garcia and Cliff.