Amongst the swathe of identikit, big-screen smartphones here at Mobile World Congress in Barcelona, one phone already stands out. It isn’t because it’s super-powerful (although it is), it isn’t because of its industrial design (although it’s quite nice), it’s because it’s the only phone that does something completely different: 3D. 3D screen, 3D camera, 3D video and 3D gaming.

If you’re sighing quietly at this stage and muttering “waste of time” under your breath, I don’t blame you. 3D has hardly taken off in the home yet, and here LG is, cramming it unceremoniously into a device that, only a few years ago, was required for nothing more strenuous than making calls, sending texts and maybe a little email.

Oddly, though,  it seems to work, and that’s largely due to its autostereoscopic, parallax barrier 3D screen. Yep, that’s right, you don’t need glasses to view content on the LG Optimus 3D – it comes right out of the screen at you.

I don’t mind admitting I was pretty sceptical when I first heard about this – after all, how effective can that be on a 4.3in, 800 x 480 resolution display? Well, the answer is, it’s surprisingly good. You do have to line your eyes up head on to the screen in order to appreciate it, but once you do, and give your eyes a moment or two to adjust, the sense of depth is far more convincing than I’d ever expected it to be, and nowhere is it more convincingly shown off than the device’s own 3D menu.

Hit the button on the phone’s edge and a 3D menu carousel hovers into view, seeming to rise up out of the screen’s surface. From here you have quick access to all the phone’s 3D features: the camera, the dedicated YouTube 3D app, and a handful of 3D games. Fortunately, the 3D mode doesn’t seem to affect the 2D visuals too badly either. When you’re not in one of the 3D apps or viewing 3D material, the screen simply reverts to standard mode.

But 3D is useless without content, and LG has recognised this fact, equipping the phone with twin autofocus 5-megapixel cameras on the rear, spaced 24mm apart from each other. To shoot in 3D, simply tap a toggle switch in the camera app: in 3D this gives you 1,280 x 720 resolution footage, recorded side-by-side; in 2D the video resolution is, as is rapidly becoming the norm at this year’s conference, Full HD (1080p).

Once you’ve recorded the footage, there are plenty of options: the phone has an HDMI 1.4 output, so you can pipe recordings directly to your 3D-enabled TV. You can upload with a single tap to YouTube, which supports 3D video; and you can watch those videos, and the rest of YouTube’s 3D content, on the 3D screen courtesy of a dedicated YouTube 3D app included with the phone.

The rest of the phone’s specification almost seems irrelevant, but it seems to pass muster. As already highlighted, the screen has a 4.3in diagonal and a resolution of 480 x 800. The processor – a dual-core, “dual channel” 1GHz Texas Instruments OMAP4 CPU – looks up to the job, there’s 8GB of storage and 4GB of LP DDR2 RAM to help with the heavy load of processing that 3D content. It’s running Android 2.2 (with an upgrade to 2.3 on the way), has 14Mbits/sec HSDPA, 802.11n Wi-Fi, measures 68 x 11.9 x 128.8mm (WDH), and weighs 168g.

It isn’t quite there in terms of being a finished product. On the stand we saw several falling over and freezing, but what LG has managed to squeeze into a smartphone that still manages to feel slim enough to slide into a (large) pocket is nothing short of remarkable. What remains to be seen is if it can keep the price down to a sensible level, and prevent the powerful hardware from eating through the device’s 1,500mAh battery. I await developments with interest.