The Danish Film Institute website had this short section written out for the game (translated):
“PROJECT 2 – as the working title indicates – Playdead’s second major project after the success of the game LIMBO. Through unique puzzles and changing scenarios narrated the story of one boy’s struggle against evil forces through questionable experiments on human bodies, trying to take over the world. The game is in color and set in a 3D environment, while the gameplay takes place as a 2D platformer.”
Though Google’s translation is a bit confusing, I think we can safely surmise that the game will feature one main protagonist (the boy) who comes to challenge an unknown evil. This evil performs experiments on human bodies in an attempt to take over the world.
Oh and it will be a 2D platformer set in a 3D environment.
Playdead has received a £1,000,000 grant from the Danish government to work on PROJECT 2 (working title). The studio has been at work on the title since 2010, with a forecasted production time of three and a half years, putting the estimated game’s release at sometime in 2014.
This title looks about as happy as the one that preceded it.