UPDATE 4.15PM BST: They Are Billions is coming to PlayStation 4! It's being ported by a company called Blitworks, which ported Spelunky and Fez and other games to PS4, and it's due to arrive in July.
ORIGINAL STORY 3.30PM BST: The long-awaited campaign for marvellous zombie survival RTS They Are Billions will be released 18th June. It's free, assuming you already own the game.
The campaign is titled The New Empire and will spin a fairly schlocky (perfectly in keeping with the rest of the game) story about said New Empire venturing out from behind impenetrable walls to reclaim the world from the infected, which are basically zombies.
It looks like there will be hero characters and as you explore across the world map, you'll uncover secrets about the past as well as new tech to upgrade your bases with. There's not much else to know, for now.
They Are Billions will also, on 18th June, add two new Survival maps. The Deep Forest will be the sunniest and friendliest of the game's scenarios, whereas the Caustic Lands will be the opposite - the game's darkest and hardest. Good luck, giggle.
They Are Billions was a breath of fresh air for the real-time strategy genre. It, in a nutshell, challenges you to build a base and protect it from waves of enemies. These trickle in at first but soon they swarm, and even one rogue infected inside your walls can cause a devastating chain reaction in turn. It's bloody hard and exhilarating as a result, and it's success has caused copycats, the most notable being Funcom's Conan Unconquered. It's not as good.