There is improvements in everything, the art, the story, the characters, and I would say even the music (that was already great) got better - as the opening song felt connected to the anime and not taking on the existentialism of the movie.... even Motoko got an improvement in her wardrobe! I mean, looks like she got a pay rise and finally was able to buy some pants.
Some of the "stand alone" episodes were great with great plots and characters, like the second episode that had all that Taxi Driver feeling on it - this one really got me into the SAC2 as it showed it wasn't going to be just another police drama - and the poker one was also great - is that story true? Maybe we will never know... although I think some episodes were very poor, like the one of the blind girl and the one of the young drug dealer, but still, there is a great improvement in all plot development and the stories told.
There is also lots of references to the manga, and stills a complete different serie from the manga and the movie, but unlike SAC, SAC2 is actually good and felt refreshing and got me excited to see what's next on Ghost In The Shell universe.
Oh! And Tachikomas, you are the best!
