I believe the developers of Starwars Episode III : ROTS use their own engine.I'm a big fan of the Jedi Knight series (Jedi Outcast and Jedi Academy), those used the Quake 3 engine.Those are fantastic games if you ask me.I first thought the new episode 3 game was the third installment of the Jedi Knight series, but it isn't the case.From what I've seen it looks more like a beat'em up rather than an action adventure game.The gameplay is glitchy, but it's too early to judge the game.I think that the two JK games perfectly translate the feeling of being a jedi in a videogame, please go try them out(there are demos available).