When Baby gets Johnny to come with her to see Penny right after his dance with Vivian, his shirt is open halfway and he is not wearing an undershirt. When they get to Penny's room, his shirt is open all the way to his waist and he is wearing an undershirt.
In Penny and Baby's dancing scene, Baby has her dancing shoes and her Keds on for the same dance.
At the beginning of the scene, she is wearing her Keds, but then a montage starts where she is showing going back and forth between wearing Keds and dancing shoes, just as shown in the original movie.
The first time Baby goes to Johnnys cabin she enters through a screen door. The next time the door is seen is when Seagals character beats on the wooden door and the screen door is gone, never to be seen again.
When Johnny is departing from the camp for good, he loads his luggage on the red pickup truck and kisses Baby good bye. But instead of departing on the pickup truck, he jumps on his motorbike and leaves, leaving his luggage behind.
As they are loading the luggage in the truck, his cousin says "I'll drive down on Saturday" obviously meaning that he will deliver the luggage to Johnny then.
When the Houseman's are driving to the resort at the beginning of the movie the gear selector is approximately the 1:30 position. This would reflect it's in the Park position. The Drive position would be approximately the 3:00 position.
Lisa's ukelele chords don't change in time with the music.
The story took place during the summer of 1963. In this version, a young guitarist is playing Bob Dylan's "Don't think twice, it's all right", which was released on Dylan's album "Freewheelin" in May of 1963, making it less than likely that the young man would have heard it yet, never mind recreating a polished performance of the song.