Although parts of Republic Commando see you heading out on your own to complete solo objectives, the bulk of the game will put you in command of one to three elite Republic Commandos whose combat abilities match and often exceed your own. If you attempt to play this game as a regular FPS, in which you charge ahead and attempt to kill every enemy by yourself, you're going to die--a lot. Success depends on your ability to maximize the effectiveness of your comrades.
Commanding Your Squad
As squad leader, you'll have five general commands to issue to your team.
Search And Destroy: In S&D mode, your squad will head out a short distance in front of you, scouting territory and opening fire on enemies that they see. They don't get too far from you, which lets you keep an eye on them, at least. We personally didn't find this to be too useful of a command, for a variety of reasons. Mostly, this is because we just liked to be in front of our squad, scouting for dangers and enemies in the path and assigning them to positions as we saw them become available. It does have the benefit of increasing your own survivability, though, since your teammates can take a lot more damage than you can, and are thus much more capable of surviving an unexpected assault than you are.
Form Up: In Form Up formation, your squaddies will attempt to stay near you when you're standing still, but will follow behind you when you're moving. We used this far more often than S&D, but it really is going to be a personal preference as to which one you'll choose. We found that this let us trigger in enemy spawns and get an idea of what was going to happen in a given fight before issuing further commands to our troopers or getting them to move forward and fire on the enemies. If you do use Form Up, you can expect to have to retreat quite a bit, just to get behind your more expendable squadmates, but this isn't something that you'll be immune to in S&D mode, either.
Secure Sector: Secure essentially means "Stay Put!" When your soldiers are issued this command, they'll hold up in the position to which you're pointing when you first issue the command. This is most useful for keeping them well out of the line of fire while you move forward and scout or have to move somewhere where you just don't want them to follow you. Like obedient pets, they'll stay where you tell them to and let you go about your business unfettered. You can also use this to issue a more specific Search and Destroy command, by pointing to a distant spot of land and telling them to stay there; they'll move across the intervening terrain, triggering any enemy spawns on the way, and firing on any enemies that they see. Since they're so much more resilient than you are, you can use this to put them into harm's way while you stay back and assess the situation, i.e. hide like a coward. Sometimes discretion really is the better part of valor, etc., etc.
Concentrate Fire: When you press your use key while you have an enemy in your crosshairs, you'll instruct your squaddies to ignore all other targets and concentrate all their fire on your chosen target. This can be pretty handy when it comes to taking down armored enemies like SBD's or just hearty ones like Geonosian Elites. Squadmates who are in
Cancel: The cancel command will disengage your squadmates from any maneuvers that you've ordered them to pursue, such as maneuvers, getting bacta, breaching a door, etc. When you issue the cancel command, they'll revert to the previous S&D, Form Up, or Secure command. If you're in the habit of telling your soldiers to stay behind with Secure while you scout ahead for maneuver positions, you may want to also get in the habit of tapping either the S&D or Form Up button immediately after cancelling their commands. Otherwise, your soldiers may run back into a previous room where they were waiting when you issued their position command.