Overall, it was fun but I though the first film was GREAT. This sequel was OK.
OK, minor spoilers below...
...Disney Princess stuff was good, and very funny (especially at the end when they "rescue" Ralph)
...Really no additional classic arcade game mascots / characters in this one.
...Majority of the film takes place on the 'net, so lots of jabs at popular locals (ebay, Amazon, Youtube, etc)
..No King Candy return or reference, although "The Man" Alan Tudyk (King Candy/Turbo in the original film) does voice Knowsmore here.
...NO MARIO/ LUIGI references that I could see. There was a Mario reference in the first film, I though for sure Disney would work with Nintendo to have a cameo here. But no.
...They say the word "butt" as in buttocks, ALL THE TIME.
...Felix and Calhoun feel shoehorned in. Being such major characters in the first film, they have hardly any real role here.
...My favorite line: "She's from the other studio"