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.

Zaku
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.

Gufu
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.

Mobile Armours
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.

Hart
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.

Other enemies

 * [[File:SN Spider.gif]] Spider
 * [[File:SN Pod.gif]] Pod
 * [[File:SN Enormous Cannon.gif]] Enormous Cannon
 * [[File:SN Missile Gun.gif]] Missile Gun
 * [[File:SN Beam Gun 1.gif]] Beam Gun 1
 * [[File:SN Beam Gun 2.gif]] Beam Gun 2
 * [[File:SN Beam Gun 3.gif]] Beam Gun 3
 * [[File:SN Spider A4.gif]] Spider (Act 4)

Other bosses

 * [[File:SN Aggai.gif]] Aggai - The boss of the second act.
 * [[File:SN Zugoku.gif]] Zugoku - The boss of the third act.
 * [[File:SN Green Zugoku.gif]] Green Zugoku - The first boss of the fourth act.
 * [[File:SN Enormous Weapon Ryushiferu.gif]] Enormous Weapon Ryushiferu - The second boss of the fourth act.
 * [[File:SN Gatse Bernard.png]] Gatse Bernard - The third and final boss of the fourth act.