The videogame inspired by the 2010 film inspired by the 1982 film inspired by 1982's videogames: it would be a weird enough conceptual feedback loop without the 28-year temporal kink in it.
Propaganda Games, the developer of TRON: Evolution, a companion piece to this year's Disney blockbuster TRON: Legacy, has the enviable yet tricksy job of making a game that will satisfy expectations of modern action-adventure while evoking neon nostalgia for the early days of the arcade.
So it's odd in a way that the games that crop up most in conversation with the developers aren't Battlezone and Tempest but Prince of Persia: The Sands of Time and Split/Second.
But when you think about it a bit more, you realise, it's inevitable, sensible and actually kind of appropriate to bring today's videogames into this self-referential geek group hug.
Those two games are good starting points for the two sections of the E3 TRON demo. The first and more substantial showcases the on-foot action that blends free running with melee and ranged combat against small crowds of enemies using the light disc.
The second is a light-bike section in you which you pursue a virus while enemy programs attack both you and the world around you, sometimes "de-rezzing" the virtual road under your virtual wheels.
As is the current trend for movie tie-ins, TRON: Evolution steers well clear of the film itself and seeks to carve out its own niche while fleshing out a broader mythology for its host fiction.
It's a prequel, in other words, and quite a distant one at that, set in 1989 "in the Gregorian calendar". It will be released before the film at the end of this year, and its events will be referenced in the film script as an Easter egg of sorts for TRON fanboys.
It's set entirely in the Grid, the story illustrating "a series of seismic events in the universe" that take it from Kevin Flynn's utopian vision to the dystopia of Legacy. It attempts to reverse-engineer the Legacy look - or evolve that of the original TRON - to show where the fantasy virtual world of humanoid programs had got to in 1989.
As retro-futurism goes that's an awkward balancing act, and you'd have to say it's ended up closer to Legacy, but it doesn't really matter: stark, minimal and elegant, with clear colour-coding of every enemy and friend, it's pure TRON.
That simplicity and restraint carries through to the on-foot gameplay. As the "next generation of System Monitor" created by TRON to fight living malware, platforming and combat - inspired, we're told, by parkour and capoeira - is extremely fluid, thanks to a stripped-down, logical control layout with interesting permutations and combinations.
Holding down the right trigger puts the System Monitor into a sprint, enabling him to vault and wall-run anywhere in the environment (even though the interaction points are very clearly labelled in this deliberately tutorialised demo).
The A button (on Xbox 360) jumps. Thanks to these and the necessarily simple and flat-faced geometry of the Grid, it's easy to string together graceful and flowing platforming runs.
Then you have two attack buttons, which launch a melee strike or an auto-targeted ranged throw of your boomerang-like light disc. These are modified by being used in a neutral stance, while sprinting, or while guarding by holding down the left trigger. Finally, you can assign a third special attack - in the demo, an explosive disc - to Y.