LONDON (Reuters) - British game maker Bossa Studios will release Worlds Adrift on Thursday, an ambitious adventure game designed to appeal to the Minecraft generation that has taken three years and 50,000 gamers to create.

The London-based independent games designer is pushing technical, logistical and financial boundaries by counting on gamers to build floating islands for their characters to inhabit, which other players can visit via airborne, pirate-like ships.

“Worlds Adrift allows you to go into the game and set your own objectives and go about the game however you choose,” said Henrique Olifiers, one of the company’s three co-founders.

Bossa was set up in 2010 by veteran game designers who first focused on making social games played on Facebook before switching to PC-based online games. It is best known for “Surgeon Simulator” and “I Am Bread”, which have drawn in millions of users with their physics-based, realistic movements.

Its new multiplayer online game is the first to run on the computational platform of Improbable, a second London firm which enables enormous cloud-based simulations to be created, without which Worlds Adrift’s complex, user-generated landscape would be impossible. It is far more sophisticated than prior Bossa games.

Bossa aims to create the next big European games franchise, following in the footsteps of household names such as Microsoft-owned MSFT.O Minecraft, Clash of Clans from Tencent-controlled 0700.HK Supercell, Candy Crush by Activision Blizzard's ATVI.O King, and Angry Birds creator Rovio ROVIO.HE.

Typically only established gaming companies with hundreds of engineers and hundreds of millions of dollars could develop games of the complexity of World’s Adrift which have massive creative potential and are not limited to scripted tasks.

Eight months ago, Bossa Studios raised $10 million in funding in a round led by European venture firm Atomico. It has 82 employees but is expanding rapidly with the recent funding, Olifiers said.

Improbable, whose system can be used to digitally simulate real-world locations not just for games but in product design and corporate planning, received a $502 million investment from the Softbank 9984.T Vision Fund a year ago.

“Unlike any other massively multiplayer online (MMO) game, your actions actually impact the virtual world - and matter,” says Improbable co-founder Herman Narula.

Gamers will build and develop increasingly complex islands which players can visit and interact with other game participants however they wish.

It is a massive fantasy universe designed to appeal to a younger generation of players looking to build games themselves.

The title is aimed at gamers reared on open-ended Minecraft, the second best-selling game of all time, which provides players with building materials to construct buildings and villages. It has attracted a sizeable number of players under the age of 15, although the majority of them are over 28 so far, Olifiers said.

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During development those gamers have created 10,000 islands, 450 of which will feature as the game launches in “early access” mode, meaning that it is still under construction and subject to changes. General release is expected within a year, said Olifiers, a Brazilian games journalist-turned-entrepreneur.

Policing the game is left to players, by design, Olifiers said. Creative contributions will be quickly mimicked by others and collaboration will be beneficial. Bad behavior could prompt users to abandon islands where incidents take place, turning them into Robinson Crusoe outposts no one else visits.

The game goes on sale later on Thursday at a fixed price of 19.49 pounds, or $24.99, with no in-game purchases that can pile up costs for committed players.