Game worlds can be interesting for a variety of reasons. They might be visually distinctive, intricately detailed, impressively imaginative, fantastically believable, or just damn good fun. There are no hard and fast rules to what makes a game world great, beyond being... well, great.

You’ll see this below in our Top Five Worlds of 2012. From the vast to the intimate, the fantastical to the historic, deep space to south east Asia, each world is distinct and each world is awesome. But which is the winner? Read on to find out, then tell us we’re giant idiots that got it wrong in the comments.

While many game worlds focus on imagination, conjuring architecture and cultures from nothing, the Assassin’s Creed series has become increasingly obsessed with historical detail. Researching period architecture and historical documents to an impressive degree, Ubisoft takes the past and brings it back to life.

This is no better evidenced than in Assassin’s Creed III’s recreation of late 1700s Boston. Hugely detailed and almost obsessively built, it’s a city alive with activity. Workers graft in the docks, pigs snuffle at slurry, red coats patrol menacingly and whispers of dissent explode into screams of revolution. For all its dramatic license, it feels real.

But perhaps the most interesting aspect of Assassin’s Creed III’s world is where it deviates from the norm by venturing out into the frontier. Skipping through the trees, leaping from branch to branch on the trail of a bear, a cougar, or something a little more exotic is brilliant fun. You’re hunting prey, it’s what you’ve always done, but this time you’re doing it in a wilderness of forests, cliffs and rivers. It’s a fantastic addition.

It's easy to forget just how dull the colour palette of the original Borderlands was. Though the graphic novel-esque, cell shaded-style visuals were wonderfully distinctive, with their sketchy black borders and expressive angles, the colours were washed out and dull and the environments not as visually distinct as the art style promised. A brown-fest.

Borderlands 2, meanwhile, is a riot of colours and environmental variety. From the Caustic Caverns with its bubbling lakes of lurid green acid, to the icey blue expanses of the Arctic region right up to the flowing rivers of glowing lava in Eridium Blight, the world of Borderlands 2 looks unlike anything else.

It works so well because it ties in with the tone of the game. Borderlands 2 is over the top, vibrant and outrageous, stuffed with big characters and even bigger guns. It demands a world to match and in the East Coast of Pandora, it delivers just that. Vast, varied and colourful, Borderlands 2’s world makes looting a joy.

Mass Effect 3 is the only game on this list where the word “world” is wildly inappropriate.  It’s so vast that if we put together a Best Game Galaxies of 2012 list, it might be more appropriate. But it’s not just the breadth of the game that impresses, it’s the depth of detail and believability of its locations too.

Every single planet and location fits within a narrative that stretches back hundreds, if not thousands of years. Dip into the Codex and you’ll find backstory with info on populations, religions and cultures - every single conceivable detail. It’s a staggeringly impressive undertaking.

Of course a bunch of text in a menu is pretty useless in isolation. But from action packed battles in the shadow of Big Ben on Earth, to the bustling Citadel with its influx of refugees, Mass Effect 3 has a wonderful sense of place. Though the ending of the game left a bitter taste in the mouth of some, we can have no such disappointment with its fantastically detailed galaxy.

The city of Dunwall is one of the most imaginative game worlds of recent years, a strange and twisted place marked by almost Dickensian squalor. It’s a tight, focused environment in which developer Arkane Studios has piled detail after detail to create a living, breathing world.

It’s not a happy place. As the City Watch guards make their oppressive presence felt, the architecture slowly crumbles and rats scamper around spreading disease, all under the sickly light of a bleary sun. Wonderfully realised, you could spend hours just mooching around soaking up the incidentals.

And then there’s the inhabitants. Courtesans lured to the city under false pretenses, handlebar mustached crime bosses, corrupt parliamentarians, the attendees of decadent masquerade balls - the people of Dunwall are as fascinating as the city itself. Dishonored’s world is a towering achievement.

Far Cry 3's Rook Islands is a pretty place. All blue skies, white beaches, jungles and waterfalls, the islands' human inhabitants may be a fearsome bunch, but the location itself is gorgeous. Yet it’s not the visuals that make the Rook Islands such a wonderful place to be; it’s the stuff you can do on them.

Far Cry 3 offers up one of the most entertaining open worlds we've encountered in a long time, thanks in no small part to its wildlife. Everyone that's spent time in this tropical hell has tales of random tiger attacks, surprise crocodile maulings and general predator chaos either assisting or ruining their best-laid plans. These moments have the ability to thrill far more than any scripted moment and even better, everyone's story is unique.

And then there's the brilliantly designed outposts, encouraging personal expression through either stealth, sniping, all out carnage or a messy mixture of the three. The driving provides vehicles expressly created to be wrapped around trees at 60 miles and hour with a big grin on your face. Even the towers manage to confound expectations, offering cleverly designed little platforming puzzles. Every element works together to make Rook Islands fantastically fun.

Offering the most entertaining world of any game this year, Far Cry 3 is a triumph.