I have watched this movie almost since I was born (1981), so I may be a little partial. But, the review that said something about Big Bird is completely false and only someone who wants attention. And I guess they got it.
This is a very funny movie that does spoof the beath party movies. Don't take it seriously, including the cameos that pop-up throughout just like some of the present day comedies. It takes you for a comedic ride on the beach, day and night. Back to the Beach is for everyone old and young, even for a 20 year old.