There's some added depth in The Sith Lords in the ability to create various useful items in labs or upgrade virtually all your existing equipment to make it more powerful, but you won't feel the need to take advantage of these systems very often, since you'll be finding so much new stuff everywhere you go. Another new system involves the ability to gain or lose influence with your traveling companions, depending on whether or not you tell them what they want to hear. Your influence will largely determine whether your allies will loosen their lips (or the equivalent) with regards to some of the most important aspects of their past. It's pretty subtle and basically not that different from how Knights of the Old Republic would allow you to try to persuade certain characters into telling you what you wanted to know, but it helps flesh out your relationships with your traveling companions a bit more. Also, once you regain your lightsaber--which takes a surprisingly long time, but there's a good sense of payoff as a result--you'll learn a variety of different fighting forms with the weapon, each suited to a different type of combat situation. These are good in theory, but don't have a particularly noticeable effect in practice.​