They talk about it, I beleive, in the Q and A session, but here is one that always bugged me. When Marty gets back to what I like to call 1985 A at the end of the movie, he sees himself going back in time. THAT Marty is a buy product of 1985 A, not the regular 1985 our Marty came from. So, when that Marty comes back, we'll he have changed his universe again? It all gets too confusing when ya think about it .