Microsoft has bought Mojang, the Swedish firm behind the popular video game Minecraft, for $2.5b. The title, which has sold over 54 million copies, allows players to build structures with retro Lego-style blocks, as well as explore a large map and battle others.The deal was announced by Xbox chief Phil Spencer, BBC said. Mojang, whose three founders will leave the company, assured fans that “everything is going to be OK”. Some analysts have speculated the deal is designed to attract more users to Microsoft’s Windows Phone devices.