Following a pair of mysterious updates to widely applauded first person platformer Portal last week, which resulted in a complete alteration of its ending, Valve has confirmed the existence of Portal 2.

Although few details regarding the game have yet been released, Game Informer has confirmed that it will be “a stand-alone, full-price retail release” with “new gameplay mechanics, storyline, and some surprising new twists.”

Valve has also confirmed that Portal 2 will be released “this coming holiday season” and that it may feature a co operative gameplay mode.