Smart watches and fitness devices jostled with apps, retail technology and all-new operating systems as the mobile industry demonstrated just how all-encompassing it has become.

"Beyond the number of attendees and participating companies, the continued expansion of the event to address key adjacent industry sectors demonstrates just how pervasive mobile is in our everyday lives and how integrated it is becoming in everything that we do," says John Hoffman, CEO of organisers GSMA.

Many of the headlines were stolen by handsets from the big global brands. LG's follow-up to its popular G Pro device - imaginatively called the G Pro 2 - was revealed to have a full HD resolution, 13-megapixel rear camera and a whopping 5.9-inch screen. Able to record video in Ultra HD quality, the G Pro 2 will have a monster-sized 3200mAh battery.

Still, the G Pro 2 will have to convince Samsung diehards to jump ship from the latest incarnation of its Galaxy S Series, which debuted in Barcelona.

With a 5.1-inch screen, the S5 is slightly smaller than the LG, and also has a slightly smaller battery, though its 16-megapixel rear camera (with an autofocus speed of just 0.3 seconds) - as well as a waterproof design that's both slimmer and lighter - should see it remain the flagship Android device.

The inclusion of fitness features, a biometric fingerprint scanner and a choice of colours (white, black, blue and copper) won't hurt, either.

Samsung's Galaxy S5 can also shoot video in Ultra HD quality, something that suggests that both it and the LG G Pro 2 are running a powerful processor.

Under the hood of both is a Qualcomm Snapdragon quad-core, which is set to bring faster camera sensors and better image post-processing, as well as more impressive mobile graphics and gaming to flagship devices this year, although the Galaxy S5 uses the very latest version unveiled in Barcelona - Snapdragon 801.

So, too, does Sony's newest handset, the Xperia Z2, which claims to be "the world's best camera and camcorder in a waterproof smartphone". Available in white, black and purple, the Z2 also films video in Ultra HD quality, but adds a huge 20.7-megapixel stills camera and a new Timeshift video mode that shoots 120 frames per second.

Although it doesn't apply to Ultra HD video (which manages - like all its rivals - just 30 frames per second), Timeshift will allow slow-motion effects to be added later. The Z2 has a 5.2-inch screen and considerably more RAM, at 3GB, than the Galaxy S5.

The waterproof and dust-proof smartphone, fast becoming an industry standard, was a trend started by Sony a few years ago. But we're not convinced we'd take the Z2 snorkelling, though it is technically possible to take it a metre under the waves.

As Sony tries to pre-empt the demise of its Handycam camcorders with the souped-up Z2, it's attempting to capitalise on its Walkman heritage by adding digital noise-cancelling support to its MP3 playback.

As usual, these smartphones offer 16GB storage as standard, but all have microSD card slots essential for anyone who likes to cart around a lot of video and music. That task got a lot easier during the congress with SanDisk's announcement of a whopping 128GB microSD card.

Microsoft-owned Nokia sprung a shock with the announcement of a low-priced, handset running on Nokia X, a new app platform based on Android Open Source Project.

The formerly Windows OS-obsessed company is gunning for the money-spinning "next billion" smartphone users in emerging markets with the polycarbonate smartphone, which boasts a four-inch screen and runs on a much-tweaked version of the standard Android experience that looks much more, well, Nokia - and does away with any traces of Google.

With a basic processor, three-megapixel camera, microSD slot, a 1500 mAh battery and just 512MB RAM, it's not going to worry anyone after a serious smartphone, though an X+ version with added RAM will be available.

Apps at launch include Facebook, Skype, Spotify, Swiftkey, Twitter, Viber, Vine, WeChat and BBM.

"The new Nokia X smartphones offer a desirable alternative to cheap Android devices for consumers in both mature and developing markets... and offer a viable alternative to the Google-centric view of low-cost smartphones that is prevalent today," says Tony Cripps, principal analyst at Ovum, a company which advises on the commercial impact of technology.

"Microsoft's pragmatism in adopting Android Open Source Project gives it a chance of finally taking the global consumer technology fight to Google, Apple, and Samsung. The result, in the long term, may be a company barely recognisable from the one we know today," says Cripps.

A pair of smartphones embraced two current preoccupations. It's perhaps no surprise that, in the post-Edward Snowden times, somebody would introduce a privacy-aware mobile phone. But there's more to the arrestingly-named Blackphone than first appears.

Several privacy-focused features are added to a reasonably standard backdrop of eight megapixel camera, quad-core processor, 16GB storage, 2GB of RAM and a basic Android OS.

Privacy features include a virtual private network for secret web browsing, a built-in firewall, access to a secure cloud storage service, and a year's subscription to secure communication service Silent Circle.

The other on-trend smartphone demonstrated in Barcelona was Yotaphone 2. A clever dual-screen device that pairs a standard LCD display with an always-on E-Ink screen reminiscent of the basic Kindle e-book readers, the latter lasts for an incredible 50 hours between recharges.

But it was left to Google to bring a vision of what a completely different smartphone could look like. Although only in prototype, Project Tango is certainly an arresting concept.

Demonstrated as a five-inch device, Tango's plethora of cameras and sensors allow apps to map the user's surroundings in 3-D and tracks the movement of objects, making a staggering quarter of a million 3-D measurements every second.

If anyone thought that smartphone innovation was slowing down, Barcelona presented some powerful arguments to the contrary.