Now playing: Watch this: How to win at robot football

This is RoboCup! This annual gathering sees robotics experts from all over the planet fielding teams of battling soccerbots in a bid for robot football supremacy.

In this CNET special feature, we take you inside the tournament, revealing the goals, dives and cutting-edge technology deployed in this quirky footie-fest. This year's tournament took place in Leipzig, Germany, where robots across both humanoid and non-humanoid leagues went head-to-head.

Meet the Australian team out to defend their title, see why a change to the regulation ball has scores of robots baffled, and enjoy the sight of extremely adorable robots falling over -- then hopping right back up again. Hit play on the video above to check it out, and see more videos from RoboCup below.

Retirement from the bot-iful game

The pace of artificial intelligence is relentless, so it's not surprising that robot competitors are frequently retired from the game. We met Wheatley, a humanoid robot playing for the Hamburg Bit-Bots, and his human guardian Nils Rokita. We learned about the tech that powers Wheatley, and what's next for this diminutive goalkeeper after years of loyal service.

Now playing: Watch this: What happens when robot football players retire

Only the keeper to beat!

Crucial to success in robot football is spotting the ball. Once a 'bot has locked on, the next step is to manoeuvre itself into a goal-kicking position, by lining up the ball between the goal and its robot feet. Robot goalkeepers are poised to spring at the ball and defend, but every so often the stars align, and a shot hits home. Here are the best goals we saw at RoboCup 2016.

Now playing: Watch this: Best goals of RoboCup 2016

Robot footballers fall over. A lot

It's true -- keeping a robot footballer on its feet is no mean, er, feat. RoboCup's ultimate aim is to have humanoid robots capable of competing with human professional players by 2050, and to do that they need to master movement on two legs. Despite some extremely advanced balancing and self-righting algorithms, these robots still frequently take a tumble. Hit play below to check out the best dives, fouls, pratfalls, faceplants and falls we spotted.

Now playing: Watch this: Funniest dives of RoboCup 2016

Update 18 July: Added When robot footballers retire video.