There was a 28 year gap between Tron
Tron: The Next Day was pulled together from some extra stuff that didn't get in the movie, but will likely show up on the DVD/Blu-Ray next month. While it's essentially an epilogue to Tron: Legacy, the bulk of it is a rundown of all the behind the scenes maneuverings with Kevin Flynn's company, ENCOM. I understand why that stuff got left out of the movie. It's presented in a documentary question/answer style which might not have meshed too well and could've been a drag on pacing. On the other hand, it's pretty substantial stuff. I love the retro, archival style it uses, and Bruce Boxleitner is great. For fans of the original Tron there's a very cool cameo at the end, so stick with it until the end. It's worth it.