Markus "Notch" Persson said the game was provisionally titled 0x10c, space-themed and set in the distant future.
Unlike in Minecraft, users are "likely" to be charged a monthly fee to take part in multiplayer games.
He said the storyline involved a group of humans who were accidentally put into extended deep sleep in 1988, and woke up more than 281 billion years later.
The universe is described as being on "the brink of extinction" and users take part in space battles, looting, trading and planet mining operations.
Mr Persson said he intended the title to follow the rules of "hard science fiction".
While Minecraft's appeal centres on users' ability to reshape the environment that their character lives in, 0x10c offers the challenge of being able to program an emulated 16-bit computer processing unit which "powers" the player's spaceship.
Minecraft was awarded top prize at last year's GameCity videogame culture festival
Mr Persson said users would be able to create their own operating systems for the CPU, and once enough user-generated software had been created, people could use it "like ordinary computers" to run other games or carry out other functions.
Interesting or over-hyped? Still very early and i expect it to come out with GTA 5.