Disc Battles
While the original featured a little digi-gladiator action, the new film promises even more.
Legacy director Joseph Kosinski showed off concept art at Comic-Con that boasted a huge arena with shifting game grids that slide and combine as players are de-rezzed and knocked out, until only two are left to battle it out.
It's like a moving, live-action version of a tournament bracket - and the battles need to feel as vicious and visceral as they did in the original movie.
Light Cycles
Come on, like they weren't going to feature possibly the most iconic vehicles in CG cinema history?
If the evidence of the concept art and the teaser (see it here ) is anything to go by, the designers have done the smart thing: building on the originals and making them cooler and more 21st century (jumps, jinks, curves).
We'll get to see both a second-generation bike belonging to Jeff Bridges' Flynn and a fifth-generation vehicle, as well as off-"road", four-wheeled vehicles.
A Return To Flynn's Arcade
Kevin Flynn's (Jeff Bridges) '80s hangout - a bleeping neon, gaming cathedral crammed with kids and soundtracked by a rockin' jukebox - is one of the most important locations in the original, so surely there's a nod?
Again with the spoiler alert! The scene we were shown in San Diego sees Garrett Hedlund's Sam Flynn turning up at a dark and dusty Flynn's, only to kick the jukebox into gear and light up the machines.
A David Warner Cameo
While Sark, MCP and Dillinger (all played by Warner in the original) were defeated or jailed, and it's unlikely that the new movie will feature a return from any of them, we'd love to see Warner involved in some way, even if it's just a vocal cameo.
The man is a genre legend and he's a big part of why the original is so much fun.
Shiva
Shiva is the huge, complicated-looking laser that deconstructs Kevin Flynn in the original and transmits him into the computer and onto the game grid.
While the laser's manufacturers - the evil ENCOM company - looks to be making an appearance in the film (according to spy snaps from the streets of Vancouver) we're hoping it's Shiva that Sam Flynn uses to dive into the world of Tron.
No 'Re-Imagining' Of The Original
Too many movies take the original idea from an older film and try to twist it into something new and relevant to current culture.
Here's hoping the Tron Legacy team are aware that this rarely works and just pisses off fans of the original pics - who, 'fanboy' sneers aside, are the crowd who will push the flick from cult hit to mainstream smash.
Thankfully, everything that we saw at Comic-Con points towards Legacy being a proper sequel that keeps the first movie's plot intact and uses it as a jumping off point to tell a new story.
