A Data miner Tyler McVicker found in the distribution of the free game Aperture Desk Job for Steam Deck a mention of the unannounced Citadel game from Valve.
Its development began at least in 2019. The game is a hybrid shooter and first-person strategy game. Citadel has a class system and two factions – the Rebels and the Alliance. The game features a single-player campaign and item-related abilities. They can be active and passive.
Another gameplay feature is AI bots. They have a dynamic system of behavior that depends on stored memories.
According to McVicker, three projects are mentioned in the Aperture Desk Job – the continuation of Half-Life Alyx, the Source 2 port of Counter-Strike: Global Offensive, and the game in the Portal universe.