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.
Unusually for a game of this type, there are no combos to learn, and simply button-mashing your way through the small, agile groups of enemies doesn't really help either.
Combat in TRON: Evolution is a game of light tactics, managing the space around you and your stances. That ties in neatly with the fact that health and energy (both in pretty short supply) are charged up by performing parkour moves in certain lit areas.
We'd like to see this implemented in more interestingly-designed and less cramped confines than evident in the demo, but it definitely has the potential to be an interesting variation on third-person brawling, and the need to constantly evade and then re-enter the fray keeps things moving nicely.
Defeated enemies yield XP. Yes, TRON: Evolution, along with every other game released in 2010, has a levelling system. There are 20 levels' worth of it in the single-player, extended to 50 by taking part in the competitive multiplayer, which supports both on-foot and vehicular combat.
However, your character is persistent across both, and any levelling done in multiplayer can be brought back into the story mode. As well as improving your attacks, new levels will yield new toys like the explosive light disc.
On the light cycle - there will be other vehicles available, including (yes! Battlezone!) a tank. You're not restricted to the iconic 90-degree turns of the 1982, the rationale being that they've evolved as machines in the past seven years.
It's a straight and very simple action racing game, with throttle and brake and a light disc attack to use against enemy bikes the only controls.
For the most part, you're simply dodging the trails of enemy bikes, Recognizers (those menacing crosses between a Space Invader and a triumphal arch) that come down to block off routes, tank rounds and the orange pixellated holes that splash around the environment as the enemies try to de-rez it around and underneath you.
With muted sound and effects in this build of the Unreal 3-engined game, it doesn't carry the sense of speed it should, the light-bike's handling lacks any kind of feel, and the rather digital trial-and-error of dodging the hazards along the course keeps killing the momentum, rather than keeping you teetering on the brink.
It looks cinematic and dramatic enough, but it's just not involving to play. Riding a light-cycle is absolutely crucial wish-fulfilment for TRON fans, so we hope Propaganda gets the chance to develop this mode further.
Judged as a movie tie-in, TRON has some promise, not least because it has the luxury of its own time-frame and getting to look to videogame rivals for inspiration rather than shoe-horning a film plot into videogame form. As an action-adventure, there's a solid and thoughtful basis to build from here, too.
As a TRON fan's dream though - as a chance to step into that virtual world burned into our retinas all of 28 years ago - it's still got a way to go.
TRON: Evolution will be released in "holiday 2010", before TRON: Legacy.