2. The Callbacks To The Original Were Appropriate
They say that the more things change, they stay the same. This old bit of colloquial wisdom is as apparent in Tron Legacy as it is appropriate. Everything from Kevin's bedtime story to Sam remarking how huge the door to ENCOM Tower is (much like his own father did in the original) to even the fact that Dillinger's son is on the board of ENCOM calls out aspects of the original without being hokey throwbacks. Though some, such as Sam living in an old Dumont Shipping office, aren't as pronounced; they still bring back memories of what happened before. It's as if Sam's life, even in his father's absence, is destined to take him into this same world that his father once fought for. Perhaps the biggest reason these callbacks seem appropriate is because Sam, and by proxy the audiences of today, are being taken on the same journey that Kevin and the audiences of the 1980's were taken on when Tron hit theaters back in 1982. For the new audience enjoying this film independently, it's all just part of the universe. For the seasoned fan, it's a fun reminder of events and persons that had previously been present. Having the foreknowledge of the first film isn't necessary, but it helps enrich the environment of the sequel that much more.