These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Alan Bradley: Given the prices we're charging to students and schools, what improvements have been made in Flynn...er, I mean, Encom OS 12? beat CEO: (who has no real idea) ...yeah this year we put a "12" on the box.
Badass Decay: Kevin Flynn is less proactive in this film than he was in the first one, instead withdrawing himself from the Grid because of his inability to defeat CLU. To paraphrase Dilbert, he's actively waiting for change, which happens when Sam arrives. Once he does, the old Kevin Flynn begins to reemerge.
Fan Dumb: In an attempt to appear clever, many fans who disliked the movie note the lack of the character called Tron in a movie called TRON... Ignoring in fact that Tron does have a major presence in the movie as Rinzler. Also, it should be noted that Tron wasn't the main character the original movie, either.
Hell Is That Noise: The quiet flickering sound that Rinzler always makes. Also, the track "Fall" is backed by an electronic screech that steadily increases in pitch as the song progresses.
Moral Event Horizon: Clu is a dog-kicking program who takes pleasure in viewing and participating in games to derezz citizens in Tron City. It's not a question of if CLU crosses the line, but when. Here are some milestones:
Stealing Tron's light jet and leaving Tron to die in the Sea of Simulation after Tron refuses to shoot down the Flynns and crashed his jet into Clu's. Needless to say, much of the fanbase turned against Clu after seeing that.
And even before all of that, the genocide of the ISOs. Since he viewed the ISOs as an imperfection (as well as threatening his ability to create a perfect system, which is exactly what he was made to do), he purposely reprograms an ISO into a virus to infect and derezz ISOs in Evolution. This was not just used as a distraction for Flynn while he takes over the Grid, it was also used as an excuse to turn the Basics against the ISO population.
Turning the Games lethal, when Flynn explicitly made the Games non-lethal, which just seemed to be a dick move to punish Programs that annoyed him (and/or piss off Tron).
Narm: "KEVIN FLYNN! WHERE ARE YOU NOW?" It's the needless insertion of the word now that really drives this narm home. The fact that his CGI face looks especially plastic in this shot certainly doesn't help matters.
Speaking of which, the younger Kevin Flynn's plastic face in the beginning provided some unintentional comedy.
Kevin Flynn's line in the flashbacks: "It is our DESTINY!" It sounded like he was going to tear his mask off and start eating the crowd.
Sam Flynn looks like he's having an orgasm while he's firing those turrets during the dogfight scene. Unintentional Hilarity Ensues.
"Oh man, I'm all over this."
"Biodigital jazz, man." That is all.
Also when he laughs while describing the ISO-s, Kevin Flynn sounds like he's choking.
Castor/ Zuse's dance moves during the battle scene in his own club. Many viewers couldn't take the intense battle scene, let alone Michael Sheen, seriously because of this.
Intentional, I'm sure. It's hard to be that Narmy by accident, surely? I hope...
In the aftermath of the raid on the End Of Line club, in which some partygoers are brutally derezzed, we see a woman crying over some remains - pixel remains.
And for those of you who saw the trailers ad nauseam, Quorra's "Here they come."
Strangled by the Red String: Carefully averted. Since at the end of the movie, Quorra becomes flesh and blood in the real world, if her romantic interactions with Sam had been even a little more direct, a lot of viewers probably would have been left feeling like the whole thing was just a convenient plot device that would let the two of them passionately make some hybrid babies. Instead, they intentionally downplayed it, with it at most being a big Ship Tease. Which is actually a good thing, since the audience is actually left curious about what will happen next, instead of rolling their eyes at what could have otherwise been painfully obvious.
Olivia Wilde said that this was done intentionally — she knew that the romance would ring false.
They Wasted a Perfectly Good Plot: A frequent criticism of Legacy is that the questions of what makes the ISOs special and how Rinzler regained his identity as Tron are poorly developed.
The latter may suffer from Coconut Superpowers, because if the CGI model of Bruce Boxleitner's head had been detailed enough to be used in closeups, the scene where Rinzler says "I fight for the Users!" could have had much more impact by showing him taking off his helmet.
The latter makes more sense with a bit of Fridge Brilliance. Check the TRON: Legacy fridge section for details.
The younger faces for Jeff Bridges and Bruce Boxleitner were both realistic-looking and moderately Conspicuous CGI. In Clu's case, this was evidently deliberate.
The main problem arises because the digital younger faces use motion capture from the real actors' current faces... and neither Jeff Bridges nor Bruce Boxleitner's faces are shaped like that anymore. It's especially obvious when Clu will speak and his mouth will almost move beyond his thin cheeks.
Invoked by the Armory Sirens. They look sexy, and they certainly strut in a fashion that should be sexy... but in a very synchronized, vaguely robotic way, lacking the fluidity of typical human movement. This is hammered home when they walk backward.