There aren't many MMO expansions that change a game wholesale when it's over five years old. There aren't many that introduce entire new methods of interaction, environment types, mini-games and meta-games, graphics and more. There certainly aren't many that offer all that as a free update to subscribers. That's what Walking In Stations, the update that will bring interiors and avatars to EVE Online for the first time, proposes to do.

It's a no-brainer, you'd think. Senior producer Torfi Frans Olafsson admits that players were asking if they'd be able to walk around and socialise inside space stations before the famously complex science-fiction MMO was even released; it's simple, natural wish-fulfilment, a limb the game has always been missing.

Nevertheless, it carries with it serious risks. EVE Online may be an incomprehensible formula to many, but it's a successful one: with almost a quarter of a million subscribers, it's a solid performer that's still steadily growing in popularity five years after release, something almost unheard of in MMOs. As the producers of Star Wars Galaxies will tell you, a radical change to an established game can easily destabilise it, and alienate its audience. If it ain't broke, why fix it?

Olafsson claims that they always wanted to do this, but that PC graphics simply weren't advanced enough in 2003 to portray characters in the serious, hard-sci-fi mode - comparable to film and TV - that they wanted. Disingenuous that may be, but the first live demonstration of the game proves it was worth the wait. As far as realistic human avatars (and their clothing) goes, Walking in Stations is right up there with Quantic Dream's Heavy Rain. There's still a certain plasticity to faces, and you can expect the rather stiff animations to improve, but in anatomy, shadowing, lighting - even light reflections on PVC and leather clothing - these characters are second-to-none.

This is the only official avatar screenshot that exists at the moment. We're chasing CCP for more.

If you're particularly attached to your current 2D visage, you'll have to do your best to create it from scratch. "Rather than write a hugely complex non-linear algorithm that would translate your existing avatar, we decided that the best such filter that exists is the human brain," Olafsson says. Character customisation wasn't shown at the EVE Fanfest.

Film visuals are constantly referenced as a benchmark. The initial costumes created by artists "were very gamey - although they were cool, we felt that you wouldn't see this in a science-fiction film". Out they went, replaced by a costume designers' work that could actually be made in fabric, accurate down to the stitching. Similarly, the environment designs created by "level artists from popular FPS games" were scrapped for the work of architects and industrial designers, since stations wouldn't be used for combat, but shopping and social interaction - the things real-world buildings are used for. Film animation studios are creating assets for Walking In Stations, Olafsson boasts.

(Visit Fanfest, and you quickly learn that CCP, while a very friendly company, is also an obsessive elitist like no other. It prizes measurable performance and bragging rights above all else. Just check out yesterday's insanely detailed presentations on graphics and server performance, if you don't believe us.)

Walking in Stations will also make EVE the first game to take advantage of a new lighting technology called Enlighten from Cambridge's Geomerics. In technical terms this means real-time radiosity - the bouncing of light from surfaces to other surfaces. In practical terms, it's supposed to allow games to take advantage of the kind of dynamic mood lighting of film, and especially film noir. A Geomerics representative showed clips of Alien and Blade Runner as well as a deeply impressive tech demo. Enlighten wasn't built into the demo shown, but regardless, there were some stunningly subtle lighting and shadowing effects on display already - ambient occlusion (softer darkening of obscured areas, as opposed to hard shadows) was spectacular.

This is actually a hangar, but gives you some idea of the scale and aesthetic of stations.

When you dock your ship, you can choose to exit your pod to your captain's quarters. Your large, organic pilot's pod leads to a dressing room for choosing costume options, and a generically curvy and antiseptic space-lounge with open-plan kitchen (and a box of "protein delicacies") and animated news screen. An elevator takes you down to the station itself.

These fairly standardised digs will allow some limited customisation - sofas, tables, pictures on the wall, "frozen corpse display cabinets" - but they're mostly there as a default showcase for your avatar, and somewhere any player can immediately call home. Appropriately enough for this rapaciously capitalist game, your real investment in Walking In Stations won't be as a home-maker, but as a shop-keeper.

CCP is taking its own idiosyncratic approach to content in Walking In Stations. Instead of designing lavish environments and writing hours of NPC dialogue for players to enjoy, the game's space stations will largely be blank canvasses: promenade rows of empty sockets for players to plug their own businesses into, and even write their own content.