I really liked this film. Sequels can often be a real let down, but Poltergeist 2 explains why Carol Anne was chosen by the poltergeist, with a bit more insight into the family.
I found myself asking a few questions throughout the film - where was the older sister, and how did they get a real person so skeletal looking to play Kane. I looked it up and discovered that she was sadly strangled by her boyfriend in real life after the 1st film, quite shocking as I assumed it was just due to a money dispute or something similar that caused her to be absent. As for Kane, he was so skeletal looking because he was dying from stomach cancer and passed away in the middle of filming, hence the appearance of the beast towards the end of the film.
I also discovered that Heather O Rourke (Carol Anne) died after making the 3rd film.
Given the tragedy invovled in Poltergeist 2, they have managed to make an interesting sequel.