Just some stupid stuff on my mind
I know that Mary Mcfly said that he loved Jennifer but I think that he was a player. In the first Back To The Future movie while he was skatebording he saw those pretty women doing exercise in the gym he waved at them and all of those women waved back. Why would they wave back unless they knew him? I think that gym was a focal point in the movies. I think that back in the 50's that was the place Marty went to use the phone to call the 50's Doc Brown but he didnt get an answer the same place where George asked for a chocolate milkshake before trying to talk to Lorrain. When Doc and Marty went to the future I think that was the place that was called The Cafe 80s. When Doc and Marty went back to the cowboy days I am sure that was the saloon. In the Back To The Future game I am sure that was the soup kitchen that Kit Tannon used to smuggle his booze.
Comments
You are likely right. If you include the animated series (which was overseen by Bob Gale, the co-creator of Back to the Future), there's even more instances of this (Jennifer even breaks up with him for a short while at one point because he agrees to go on a date with another girl). Then in the comic, Back to the Future: Continuum Conundrum (which was co-written by Bob Gale), Marty waved and said hello to two girls with a roguish smile, Tiffany and Michelle, which upset Jennifer - who was upset with him already at that point because he had been acting sullen and moody ever since Doc left in the time train.
He does eventually marry Jennifer though, so he likely does grow up at some point (as I doubt Jennifer would have stayed with him for over 30 years if he kept that up).
I think that Marty being the cool guy at his school is why that he waved at the cheerleaders and they waved back. I don't necessarily think that he was the cheating sort and more that he was a teenager that liked being the center of attention. You are correct about your other theories.
I really loved this game and I liked how the Edna storyline had ended. That was hilarious that her and Kid Tannen got together and she became the stepmother to Bif. In episode 3, she can't stand Bif and tortures him mentally. It's funny that she got control over Kid Tannen and turned him into a good guy in the end, especially since when we changed the time line, Edna was kidnapped and held hostage by Kid.