PixelJunk 1-4

It's a self-effacing brand, PixelJunk. "Why, this old thing?" Kyoto's Q-Games seems to be saying. "Oh, it's just some disposable retro frippery I knocked up, don't give it a second thought." And yes, the three titles to date (Racers, Monsters and Eden) do have a certain thrift-store attitude, pinning tiny 2D sprites on mix-and-match, second-hand inspirations like Scalextric and tower defence.

But PixelJunk, especially the life-consuming Monsters, has also made a huge contribution to the ever-growing collection of exclusive games on PSN that match or beat anything on Xbox Live Arcade for style, originality and daring. They sit proudly alongside the likes of Flower, Noby Noby Boy, The Last Guy and the forthcoming Fat Princess. Having played it at last week's Sony showcase in Los Angeles, we're confident that PixelJunk 1-4 (it's a working title) will be no exception.

It's the most nakedly retro game in the series to date; eighties classics Thrust and Exile are obvious influences on this gravitational game of subterranean search-and-rescue. But it's also the most modern PixelJunk yet, flaunting a technical spectacle of physics and fluid dynamics as the player manipulates reservoirs and torrents of water and magma, as well as the rock itself, to solve the navigational puzzle of each stage.

You pilot a tiny yellow capsule through 2D cross-sectional caverns sketched in tasteful Habitat browns. The left stick controls the vessel's movement with thrusters; it has a free-floating inertia and succumbs to a gentle gravitational pull. The right stick controls its orientation through 360 degrees, aiming its rockets, which are used to blast away rock as well as destroy the rather Metroid-style organic enemies and robotic turrets that spit, lunge and shoot from the cavern walls.

There's also a grappling arm, which extends to gather pickups, drag objects and grab the stranded spelunking spacemen who wave cheerfully for help from around each level. You'll need to rescue all of these guys to open a barrier to move on to the next stage - all the living ones, at least, since you can lose them to enemies, rock-falls and lava. Save more to increase your score, which is also boosted by the yellow stars trailed like breadcrumbs around the levels, and released by enemies and rock formations when shot.

So far, so standard twin-stick shooter. But all of this is mere framework for what PixelJunk 1-4 is really about: temperature and fluids, and what happens when you play with them.