I know I'm waaaaaay behind on a post like this, considering how old this game is, but I dusted it off the other day and still love the experience it brings. I haven't played a ton of Star Wars games (KOTOR II, Jedi Outcast, Jedi Academy and Shadows of the Empire) so I won't state this the best Star Wars game, but from what I've played, it stands out the most to me.
In fact, when Disney bought Star Wars, I thought the most obvious choice for a spinoff movie would have been The Force Unleashed. It covers a good chunk of time between Episodes III and IV and bridges them better than Rogue One does.
My hope is Disney will someday give this story its due on the silver screen. I can't imagine I'm alone on this line of thinking. The story is compelling, the characters are great, plenty of lightsaber clashes and Darth Vader at his peak. I don't think it has to follow the game story to a T (never liked Starkiller taking a saber to the back and still surviving), but it's a good outline with plenty of avenues to explore.
It could simply be called: Starkiller: A Star Wars story. Or Sith Apprentice. Or whatever. The title doesn't matter. I just want to see it.