Well, some of the stuff I understood, some of it I didn't but overall, I could have been a lot happier with this film. Firstly, it didn't have as much of the cool cinematography and hell cool camera anles that the Matrix had - this one was shot more like a typical action movie, and unlike the Matrix itself, pretty much was a typical action movie. Apart from a few scenes, there wasn't as much thought required in this one.
I also got the feeling that this one was sort of tacked on - I know it wasn't, since they've always said they'd planned to do 3 movies, but that's just howw it felt to me. Plus Morpheus and Trinity both semi successfully taking on agents... I dunno about that'n.
That said, there were some good parts. We got to have a look into the deeper parts of the Matrix, and into the society of the machines. As for the sex/party scene there was a reason for it. IMO, it was designed to to contrast the machines ith humans - unlike the precise, crisp and clean machine existences, this was earthy and human - very different.