Half-Life 2, Episode 3

Half-Life 2's third DLC episode was never finished because Gabe Newell and company didn't just want to finish the Half-Life 2 ...
As part of its big Half-Life 2 20th anniversary documentary, Valve showcases gameplay footage from the canceled Half-Life 2: ...
A new documentary into the making of Half-Life 2 discusses the cancelled Episode 3, and shows footage of it for the first time.