For a breakdown of the footage that Hill viewed, just follow the link over to his site. In terms of his review of that footage, here's what he had to say (and note that THERE ARE SPOILERS HERE):
"I guess I should probably tell you folks that I'm not all that big a fan of the original 'TRON.' I mean, I thought that this 1982 Walt Disney Productions release had some terrific visuals & amazing special effects. But as for the story that actually drove the characters & plotline of this Steven Lisberger film ... To be honest, I thought that it was something of a snooze.But as for "TRON: Legacy", I have to admit that I was impressed by the nuanced, intelligent approach that Kosinski took with "TRON: Legacy." Meaning that - in order for us to buy into the digital world of TRON, to get us to actually care about what goes on inside of this virtual realm - Joseph first had to give us some characters that we could care about. And Joseph actually pulls this off with the character of Sam Flynn (who's played by Garrett Hedlund). This character basically serves as our guide through the world of TRON. Which has changed significantly since the original 1982 film...."
AGAIN, THERE ARE SPOILERS HERE!
Hill continues, "...Let me now jump ahead to the most important scene shown at that press screening. Which was when Sam was finally reunited with his long lost father, Kevin Flynn. In this sequence from his film, we actually get a sense of what Joseph Kosinski was saying. That - if you can totally disregard this film's great visuals and awesome design - when you get right down to it, "TRON: Legacy" - in its heart of hearts -- is about people struggling to make a human connection in this digital age.
"And young Flynn ... Given that it's been decades since he last saw his father, Sam is clearly overcome by emotion as he hugs his Dad. Whereas Kevin Flynn ... Clearly all this time that he's spent alone away from real humans in the world of TRON has fried Flynn's circuits. In a truly inspired performance by Jeff Bridges, you get to see this man genuinely struggling to reconnect, trying to step away from the monk-like routines that he's created for himself in order to stay sane in this virtual world. Where (to quote from The Beatles' "Strawberry Fields Forever") nothing is real. As the elder Flynn steps away from his son, saying that they'll talk over dinner, all will be explained then, you can see Sam wondering what's really going on with his father. Why he seems so distant now.
"And as for what Kevin Flynn is actually been through , what caused him to become the way he is today ... Well, you're going to have to wait 'til December 17th in order to get the full skinny on that aspect of "TRON: Legacy."