Namco's 1990 first-person shooter arcade game, Steel Gunner, is divided into four acts; the players must guide the sights of the Neo Arc police officers Garcia and Cliff as they attempt to save 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). If you are using MAME to play this game, you will not be able to make the crosshairs move by default - and you must press 9 and F2 together in order to enter the game's lightgun calibration mode. A target will be displayed in the top-right corner of the screen as the text "SHOOT IT TOP RIGHT ICON, PLAYER 1 GUN" is displayed in the centre of the screen; use the arrow keys to move the crosshair up to the target, then press Ctrl to fire at it (if you hit it, it will turn red). You will now have to press "9" again as another target is displayed in the bottom-left corner of the screen and the text "SHOOT IT BOTTOM LEFT ICON, PLAYER 1 GUN" is displayed in the centre of the screen - and again, you'll have to use the arrow keys to move that crosshair down to the target, then press Ctrl to fire at it (and again, if you hit it, it will turn red). You will then have to press "9" once again, as a third target is displayed up in the top-right corner of the screen and the text "SHOOT IT TOP RIGHT ICON, PLAYER 2 GUN" is displayed in the centre of the screen; use R, D, F and G to move the crosshair up to the target, and press A to fire at it (if you hit it, it will turn blue). You will now have to press "9" yet again as a fourth and final target is displayed in the bottom-left corner of the screen and the text "SHOOT IT BOTTOM LEFT ICON, PLAYER 2 GUN" is displayed in the centre of the screen - and again, you have to use R, D, F and G to move that crosshair down to the target, then press A to fire at it (and again, if you hit it, it will turn blue) before pressing F2 again to put the game back into attract mode. The lightguns' calibration will be saved in an NV file.
Garcia and Cliff must progress along a predefined path through each act, and have the power to shoot anything on the screen (including all background objects and even 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 (this is also indicated by the bystanders collapsing and shouting "Ouch!" or something similar). When they're low on energy, the text "WARNING" will appear over their life bars, and a warning sound effect will start to be heard from the C140 - but they will regain energy (and gain additional missiles, given that they only start out with four) at the end of all except the final act depending on how accurate their shooting was. Also, when the players enter their initials on the high score table ("TODAY'S BEST 5"), they will also be displayed on another table ("TODAY'S WORST 5") if their number of misses was higher than 120; given the amount of background objects that can be destroyed in the game, it almost certainly will be.