I finally tracked down a copy of Tron to watch again, and I swear this version is different. Iirc, the original had like 10 minutes of the outside world, then Flynn got sucked into the grid. This version has like 30-40 minutes of story that sets up the actors who would later appear in the grid.
Am I seeing things?
My recollection is a fairly substantial setup period where they introduce the characters, the power struggle involved, and the project they’re working on. But it makes sense to me that it seems way longer to you now, because the stuff inside the computer is the meat of the story.
I watched Tron again just before Legacy came out. Flynn doesn’t get sucked into the computer until about 25 minutes in.