There were a lot of twists and turns in the story to say the least. In Series 1 there was a lot of action and "brute force combat", where R2 had more of a strategic and tactical focus to it. Much of the show was predicated on calculation, very much like a game of chess (which is a common theme that arises throughout the show). As I made my way through this series, I found myself at times a little challenged to follow the twists in the plot. This wasn't so much a factor of lax scripting or plot holes, but more just from the sheer pace that the show tended to move with at times. These "temporary losses in the map" so to speak were just that, temporary. It was relatively easy to get back on track and understand where the story was moving next.
Without getting into all of the nuances of the plot, what Code Geass: Lelouch of the Rebellion R2 does is really throw the idea of right and wrong, just and unjust, good and bad, on their heads and begin blurring the often perceived lines of clarity. The theme of good coming from evil is also a commonly recurring element, leading to questions about the nature of some characters as they are originally portrayed in the first series.
Items such as animation and character design hold true to what they were in the first series. While this isn't always the case in some anime shows that span a larger timeline (such as Slayers), I was glad to see that R2 retained the same look and feel as its predecessor.
In terms of music, I was more partial to the soundtrack of R2 over the first season. I found that the music did a better job of setting the tone throughout the show, while the intro and ending themes did give the sense of adapting with the story.
Overall, I would highly recommend this series. For those who want to watch something that provides some serious mental stimulation, Code Geass: Lelouch of the Rebellion R2 is an excellent title to check out!