Citadel, according to a dataminer, is a new game designed especially for Steam Deck: it would be a mix between Half-Life and an RTS.
Tyler McVicker – creator of the Valve News Network – recently reported some information uncovered via datamining of Valve software (such as Steam, DOTA 2 and so on) regarding Citadel (codenamed), a cooperative FPS / RTS game described as a mix of Left 4 Dead and Alien Swarm, or as a child between Half-Life and an RTS .
Citadel, according to McVicker who has been researching the game since 2018, is in development with a particular focus on Steam Deck and console controls. Citadel is still in full development and should be available in a year and a half to two years . Valve is mostly focused on the production of Steam Deck and its distribution now, but not for that has put aside the work on the game: this tells us McVicker.
McVicker himself points out, however, that everything is just a rumor and that it is not official information. The dataminer reminds that he does not represent Valve in any way and that only the company will finally be able to decide what will become of the Citadel project.
Certainly new original projects from Valve would not be unpleasant, especially if designed to take advantage of the features of Steam Deck.