CODE GEASS: LELOUCH OF THE REBELLION R2 gets off to a start that is both slow and absurdly abrupt, as we're suddenly introduced to a situation in which the main character(Lelouch) is behaving in ways that seem drastically out of character in several aspects, with no idea how he got there and where he suddenly picked up a strangely creepy little brother that'd never been mentioned before. This is resolved within the first few episodes when we get an after-the-fact explanation of what happened following Season 1's abrupt cliffhanger ending, but weakens the overall story somewhat.
However, Volume 1 also briefly introduces deuteragonist Li Xingke, who is sort of what happens when you take Lelouch, his rival(Suzaku), and toss them both into a blender with a heavy supplemental dose of awesome - unfortunately, he doesn't do anything much just yet. But the concluding episodes to this volume, while uncomfortably reminescent of last season's episode 21 in terms of a major plot point that is introduced, set the stage for the show to REALLY take off running, and Vol 2 and onwards much more favorably compare to Season 1.
All in all, while as most sequels do it can't quite measure up to the first season, it's a fairly solid start to an excellent follow-up.