Once you have inserted your coin(s) into the cabinet of Midway Games's 1991 horizontal scrolling shooter arcade game Strike Force, and pressed either Start Button (to begin the game as player 1 or player 2), the following text will scroll up the screen (but you can press your side's Firing Button, to skip it):
The shuttle will then beam your ship(s) down to the planet Phobos, which is named after the first moon of Mars; you can fly in either direction over it, but your objective is to destroy all the Saurians (and other, unnamed enemies on it) (use the scanner at the top of the screen to identify their positions). You will also have to pick up the special weapons that litter its surface to add them to your arsenal, and rescue the colonists before they are transformed and turn against you (but you can still pick them up after transformation) - and, if you should take too long over clearing the planet (or returning to the shuttle after doing so), three alien drones will approach, and you will be advised to clear the planet immediately. Once you have returned to the shuttle, you will have ten seconds (the time shall increase to maximum of thirty seconds as the game progresses) to direct it to one of the twenty-one remaining planets: Pterra, Erosia, Skarro, Brimstone, Nemesis, Xymox, Arobia (a pun for Arabia), Toxico (a pun for Texaco), Irakk (a pun for Iraq!), Pyllar, Cyberia (a pun on Siberia), Krypton, Dryan, Amazon, Andreas, Maelstrom, Zukalt (a pun on the German word for "so cold"), Phoenix, Petrol Deus, Boing and Demnos - but, if the Federation Supply Ship is passing by, you can direct it towards that instead. Both players will have fifteen seconds to select one of the eleven different types of special weapons with their joysticks and press their Start Buttons to buy them in exchange for a Trilithium Crystal (if you do not have any Trilithium Crystals, you will have to insert another coin and use its credit to pay for it); also, if a Saurian dreadnought retakes a previously-secured planet (causing it to start flashing), it shall force the shuttle back there for the closest thing this game has to a boss battle (if it is close enough). Once all twenty-two planets have been secured (regardless of how many had been more than once), the shuttle will automatically head for the Saurian Mega-Star "Apocalypse" - and if you are lucky enough to reach the core and destroy it, you will receive 25000 points for each planet you saved as they appear in a clockwise circle (and if you saved all twenty-two, the text "ALL PLANETS SAVED!!! AWARD 1 MILLION." shall appear on the screen). The game will then go into high-score mode; your scores will most likely be the two highest ones for the cabinet to date, so you should enter your initials at the top of the table with pride (regardless of which way they are positioned). The text "YOUR RANK IS DEFENDER" will then appear, on both sides of the screen (the game uses eight different military titles to reward players' accomplishments: Gunner, X-Pilot, Major, Colonel, Commander, General, Avenger, and Defender) - and the screen will then fade out to the front page of a newspaper "War Update Vid-News", with the headline "MEGASTAR DESTROYED!!!" with sub-headline "SAURIANS DEFEATED. STRIKEFORCE TEAM SAVES THE DAY!!!" with the story "THE LONG, BLOODY WAR WITH THE SAURIAN EMPIRE CAME TO A TRIUMPHANT END FOR ALLIED FORCES THANKS TO THE HEROIC EFFORTS OF STRIKEFORCE" below it. A digitized monochromatic photograph of the game's staff is also displayed to the right of the story with the text "MARINES REJOICE! (TOP) ERIC PRIBYL, CHRIS GRANNER, RICH KARSTENS. (BTM) JOHN VOGEL, TODD ALLEN, JIM GENTILE." below it, and with the aid of stop-motion animation and speech synthesis, they will cheer from the HC-55516; the text "THE END" will then appear on the screen, but a "?" will appear under it when a rocket-riding Saurian flies into view from its left side and off its right one. The game will then go back into attract mode - but it is your choice if you want to play again with that free credit the game awarded you after destroying the Mega-Star's core, or leave it for the next player to come along.