Half-Life 2: Episode 4 was being developed by Arkane; now cancelled

Half-Life 2: Episode 4 project that was being developed between Valve and Arkane Studios. An anonymous source provided the site with screenshots and animation tests for the now cancelled project – also known as Return to Ravenholm – showing new textures, locations and a curious new HUD element.
While we can’t be 100% sure of the legitimacy of the screenshots, Valve’s Marc Laidlaw confirmed the existence of the project last year