Though the first had its moments, the viewer can tell that the second is a blatant parody of itself. Modern films have begun to lose that tongue in cheek aspect, as seen in the earlier James Bond films or pre-Terminator 3 Schwarzeneggers. It's ridiculously OTT, presenting a stupidly comic version of the future that ridicules sci fi movies that look at the future through the lens of the era; and it only improves the closer it gets to 2015. The first one was more nostalgia than parody, which although pulled off magnificently, loses out narrowly to the second.
My problem with the first movie was that it wasn't dark enough but in the 2nd movie you mix the right amount of comedy and the right amount of darkness in the first movie i think it was mainly comedy but in the next one they mixed comedy and darkeness perfectly