The second and third movies, Porky's II (The Next Day) and Porky's Revenge never did live up to the first movie. Clark bowed out of the franchise after the second movie, and by the third movie, none of the actors could pass for teenagers in their senior year of high school. Both the first movie and the second movie dealt with the racist south. The second movie especially lampoons the KKK and the racist southern preachers with the story set around the fact that a Native American transfer student was cast as Romeo - alongside a Caucasian Juliet in the high school play, and the protagonists taking down the racists. The third movie, released in 1985 was about Porky blackmailing the Angel Beach basketball team as revenge for the kids destroying his club in the first movie.
As far as the DVDs go, the set has all three movies on separate discs. The first movie has the most extras, with the commentary track by Bob Clark being the most extensive, and then a 13-minute making-of documentary. Then, each disc has the trailer and some tv spots for the respective movies. Definitely not as much as some box set releases get, but given that none of the movies were a critical success, that is not all that surprising.
Overall, the first movie is good and the other two fall in quality. There is a lot of nudity in each movie, including full-frontal nudity from both men and women, which was highly controversial back then. The themes of racism and antisemitism in the first two movies would be much more of a big deal now, and chances are the movies could not get made the same way today as they did back then. Porky's Revenge is more of a straight-up comedy (and is also the worst of the three). None of the movies were as good as other coming-of-age-teen comedies or dramedies of the era like Fast Times at Ridgemont High and Sixteen Candles, but it was definitely a precursor to the more raunchy teen comedies like American Pie that would come out years later. For most people, the movies will be a nostalgic blast from the past, and for that, this is a good set.