Half-Life 2: Episode 3 would've included an ice gun with 'kind of like a Silver Surfer mode,' and Valve just released footage
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 story arc, but to do something big and innovative with the game design, and as Newell put it in a new documentary, he was "stumped."