In single-player mode, the player and squadmates do not die when they run out of health, but rather are incapacitated. If the player character is downed, the player can order the squad members to attempt to revive the player or to continue with their current orders. Therefore, the game is only truly over when the player and all members of the squad are incapacitated at once or if the player is downed in a position his squadmates cannot reach (such as chasms). Certain missions may require squad members to split up to accomplish various isolated objectives, and in such scenarios, where the player is operating alone, losing all the player's health also results in a game over. While reviving a downed commando restores a small amount of health, bacta charging stations are necessary to fully regain it.
Weapons can be acquired in both single player and multiplayer. Throughout the campaign, the player always carrys the compact DC-17 and a blaster pistol with unlimited ammo. The DC-17 can be configured into an assault rifle, sniper rifle, and grenade launcher. The player may also use weapons dropped by enemies.
Republic Commando maintains a first-person perspective throughout the game, presenting the story from the eyes of Delta Squad's squad leader, RC-1138 (Boss). His squadmates include RC-1262 (Scorch), a talkative explosives expert; RC-1140 (Fixer), a skilled hacker and a dedicated soldier, and RC-1207 (Sev), the squad's sniper who enjoys racking up kills. Information is received via radio commands from a Clone officer (referred to as "Advisor"), and a text-based objective list with a pop-up objective tracker arrow that points the player to the next objective.
Plot
The game is set during the events of the Clone Wars that started at the climax of the movie Star Wars: Episode II – Attack of the Clones. In the game, the player takes command of a Clone commando team, made up of elite Clone troopers. These Clone commandos have been specially bred at the clone factories on Kamino. The commando team travels to various locations in the Star Wars universe, including Kashyyyk, Geonosis, and the derelict spacecraft Prosecutor. About two years pass from Delta Squad's first mission to the end of the game.
At the beginning of the game, Delta Squad is deployed from the RAS Prosecutor individually into the front lines of the Battle of Geonosis. There, Delta-38 ("Boss", the player character) meets up with squad mates 62, 40, and 07 ("Scorch", "Fixer" and "Sev" respectively). Delta-38 has been selected to lead this unit and guides them on their mission to assassinate the Geonosian leader Sun Fac, chief lieutenant to Geonosian Archduke Poggle the Lesser, one of the members of the Separatist Council. After accomplishing this objective, Delta Squad sabotage the droid factory underneath Sun Fac's headquarters, disable an anti-aircraft bunker that is wreaking havoc on the Republic Army's air forces, and then sneak onto a disabled Separatist Trade Federation Lucrehulk-class Core Ship and steal important launch codes to prevent the Separatist fleet from retreating, escaping seconds before the ship is destroyed.
A year into the war, the now-veteran Delta Squad is sent to investigate the derelict Acclamator-class Republic Assault Ship (RAS) Prosecutor, their former home before being deployed to active duty. The team splits up to investigate, when they begin to lose contact with each other one by one aboard the ship. After entering the ship, Delta-38 ponders why the interior of the Prosecutor remains deserted and eerily quiet, when he is suddenly ambushed by Scavenger Droids, which are responsible for the communications disruptions between the squad members. Delta-38 continues fighting off Scavenger Droids and comes across Trandoshan Slavers and Mercenaries. 38 singlehandedly fights his way through the ship, collecting information from the ship and rescuing his squadmates. Once Delta Squad is together again, they destroy a jamming device in order to restore ship-wide communication. Delta Squad then destroys a Trandoshan dropship in a hangar, accidentally blowing up the hangar's shield regulator in the process. Immediately afterwards, a Lucrehulk-class Trade Federation Battleship drops out of hyperspace nearby, as the Trandoshans were about to sell the vessel to the Separatists in exchange for droid support. As Republic reinforcements are en route, Delta Squad defends the vessel against hordes of battle droids, destroying the docking shield regulators, allowing nothing to pass through. They then proceed to the gunnery deck to activate the fire control computers, a lengthy process that they have to perform while under heavy droid attack. Successfully activating the computers enables the Prosecutor's turbolaser cannon batteries to open fire on the Trade Federation Battleship, saving the Prosecutor and working in conjunction with the timely arrival of a second Republic ship, the RAS Arrestor, to ultimately destroy the Trade Federation Battleship, shutting down all remaining battle droids on board the Prosecutor.
As the war drags on, Delta Squad participates in increasingly dangerous missions. A plea for help is heard by the Republic from the Wookiee homeworld of Kashyyyk. Delta Squad is sent to rescue General Tarfful from Trandoshan slavers and mercenaries. After encountering General Grievous himself in one of the compounds and fighting off his MagnaGuards, they learn of the full ramifications of a Separatist/Trandoshan alliance. Delta Squad sabotages a vital Trandoshan supply depot and proceeds to the key city of Kachirho, setting in motion the Battle of Kashyyyk. There, they move through the Wookiee tree city, securing important objectives and battling against hordes of advanced battle droids. They destroy a bridge center-span at Kachirho, strategically splitting the droid army and cutting a large part off from its reinforcements, and proceed to secure the Citadel. Soldiering through the most elite Separatist forces, Delta Squad once again splits up to man four heavy anti-aircraft turrets in order to assist in the destruction of a Separatist destroyer hovering over Kachirho. Once the ship is destroyed, Clone Advisor CC-01/425 orders Delta Squad to regroup at 38's position. However, Sev reports that he's under heavy attack before all communication with him is lost. Delta Squad prepares to rescue Sev, but Advisor orders them to evacuate immediately. As they head out on the gunship, devastated by the apparent death of Sev, they are debriefed by Jedi Master Yoda. A huge Republic fleet is seen deploying outside the gunship, as the now three-man Delta Squad prepares for another assignment in the battle.
