The first one was successful?
It was, but success does not mean it is good, just that numerous people bought it. I quite frankly got frustrated with it several times. It's an okay game, but could have been better. The annoying glitches took away from the quality of the game. There was a glitch that would cause the game to cease to count your kills and hidden holocrons you acquired, preventing you from unlocking achievements/trophies on depending whether you're playing on the xbox 360 or ps3. I suffered from that glitch as well as getting trapped inside rock formations, and since you are required to defeat bosses in a finishing move animation, I was trapped on a level when I threw Kazdan Paratus off the stage, and he would not return ( he got stuck somehow). I had to reload, which was a pain. Upon completion of the level I saw in my kill count that my count for Kazdan Paratus was 2 (The counts carry over from 1 play to another). He was "dead," but as I mentioned, the finishing move is required.
I have only downloaded the 1st downloadable content. I did so, as it was 50% off. Yet, I still feel it was not worth the $5. I found it pretty boring. Unlike the main story, beating it on the highest difficulty does not yield you the achievements for completing it on the lower difficulties. Probably to make it last longer, as the thing is very short (can be done in 2o min if I recall correctly) , and you get more playtime out of it by having to complete it various times.
Here's hoping they learned from their mistakes on the first, and the second is better.