In the documentary, Valve has also revealed completely new and previously unseen footage of the cancelled project. It showcases a new enemy blob-shaped shapeshifting enemy type that could move through grates or split up into smaller versions of itself. Also shown off as a new weapon called the Ice Gun, which did exactly what its name suggested. 

In the documentary, members of Episode 3’s development team reveal that Valve had developed multiple levels of the game, before the project was put on hold so that the development team could help wrap up Left 4 Dead’s development. By the time that was done, however, it was decided by Valve leadership (including Gabe Newell) that it was too late to return to Half-Life 2: Episode 3. 

You can view the full documentary below.