To play the mod, you typically need and the Source SDK Base 2013 Singleplayer (set to the upcoming beta branch) installed on Steam. Primary Sources :
The Closure on ModDB : The most common official host for the mod files.
While ambitious, the mod has a mixed reputation. Some reviewers on Reddit praise its creativity and scale but criticize the level design for being maze-like and the cutscenes for being unskippable or lore-inconsistent. Half-Life 2 - The Closure (Episode 3) - Steam Community
is a major fan-made modification for Half-Life 2: Episode Two that acts as an unofficial sequel, aiming to provide a conclusion to the cliffhanger ending of the official episodic trilogy. Mod Details