Tomb Raider: Underworld

Arse is the new tits. That's just one of the trends I noticed emerging from this year's E3, which is to gaming what London Fashion Week is to people who make trousers for a living. Other trends include games set in post-apocalyptic American cities (I counted approximately 47,000 of these), and games about shooting mud-coloured monsters with no hair, gaping maws and the gait of an irritated orangutan (I counted approximately 47,000 of these, of which 47,000 were set in a post-apocalyptic American city).

But back to the arse. In fact, there's no getting away from the arse if you're sitting in an E3 demo of Tomb Raider: Underworld. They're showing off the underwater level, or at least that's what they're pretending. They're really showing off Lara's new wetsuit, which is reasonably sensible from the front. But when she turns round you see it's barely covering her spectacular buttocks; the bottom half of the suit appears to have been sprayed on using a stencil made by drawing round a Dairylea triangle.

So there's Lara's arse, bold as brass. It's bobbing away in the deep blue waters of the Mediterranean, free to explore without worrying about that air meter now Lara has scuba apparatus. Very practical. Unlike the wetsuit. Or the lack of fins. But at least Lara's got a harpoon gun, which she's using to take out a shark. A red reticule appears around it, suggesting the targeting system hasn't changed much. The Eidos marketing man presenting the demo (the people who actually make the game still can't be trusted to talk about it, apparently) explains that while Lara's 9mm guns will work underwater, bullets won't travel too well. Sticky grenades, however, are very effective.

She also has an underwater camera. Eidos Man shows how you can switch to the first-person viewfinder perspective and take snaps of your adventures. Then, we're told, you can upload them and share them online. I doubt anyone I know would be remotely interested in a photo of a shark being harpooned by a videogame character I happened to be controlling at the time. But then I'm not interested in whether anyone I know is feeling hungover or looking forward to the Radiohead concert or thinking about buying a new fridge, and yet Facebook remains triumphant.

Now Lara's arse is swimming through a stone corridor, at the end of which is a large circular door. This is familiar territory - the door has three holes, and Lara and her arse must go off and find the three axels that fit into them. However, she no longer possesses a Mary Poppins-style backpack capable of holding a dozen guns, 73 medi-packs, half of the treasures of the ancient world and the contents of an Ikea. If an object - such as a giant axel, for example - won't fit in the backpack, Lara will just have to hold it. She can still swim and run, and shoot too if she has a free hand. In addition, objects can be used in melee combat.

Lara has some new and improved equipment to help her out, including a utility light that won't run out of battery and a PDA complete with sonar feature. Send out a ping and it'll bounce off all the hard surfaces within Lara's field of view. This is then used to start constructing a 3D map, which shows the surrounding area as geometric shapes. As you move around levels, you can keep pinging to build up the map. The idea, explains Eidos Man, is to give you a proper reference for navigating a 3D environment - something that can be hard to do with only a 2D map. The sonar feature works both underwater and on land, and looks like it could be very useful for avoiding those "Where's that door I came in again?" moments.