This is not only the game that got me into Bioware, but it might be my first RPG I actually tried to get good at and learn the mechanics of; setting the oath for my love of RPG's as a whole. It's not perfect and it can be argued if it aged well or not, but it's a lot of fun to play and has a great story if you let it suck you in.
The game itself follows the tried and tested D&D rules like many Bioware games, with this game using a variation of 3rd/3.5 Edition rules; at least that's what it reminded me of. Put simpler; Dexterity for guns, Strength for melee. Feats add to abilities, skills and the like and force users essentially get a magic bar and the choice of powers every few levels. There's also the use of the ever present Dark side/Light side choice in Star Wars. This is mainly to affect opinions of your team mates in some conversations, but it also provides cheaper Force use for certain powers if they conincide with your alignment (Spamming Lightning never became easier!). It's nice simple, it works. There are a few useless powers and feats, but really, that's subjective on my part and there's probably someone out there for every combination.
As for the atmosphere and world building, I won't go into too much detail. It's Bioware, by this point we all know that Bioware can excel at this. I will say though that by being set years before the movies, there's a nice chance to set up some new villains and situations that provide a nice background to everythgin; I'd say the whole story is a huge point in the games favour.
Like I said though, the games not perfect. It's hard to ignore that the levels you visist are essentially successions of corridor after corridor. There's one path that reaches the end, sometimes you divert off it for secrets, but the apth is always there. The game tries to disuguise this, and I admit, it took me a while to catch on, but it's there, and hard to ignore once you notice. Not to mention, without spoiling it, the end game can feel a little sloggish with how it handles itself. It can be fun, but your first time, without expecting it, prepare for a lot of reloads.
Still, despite all that, the game's a tonne of fun to play and I love to return to it once in a while. I'd easily say it's worth every penny and should be played by everyone at least once; wholeheartedly reccomended