Looking at my Steam library I started to forget what I had finished, so below is a list of games where I have completed the main story or task to look back on. I will be updating this same list as I play or remember more, rather than making a new list.
Games I have completed: Among the Sleep Aperture Tag: The Paint Gun Testing Initiative Battlefield: Bad Company 2 Bioshock Driv3r Duke Nukem Forever The Elder Scrolls: Skyrim event[0] Fallout 4 Fallout: New Vegas From Dust Gone Home Grand Theft Auto IV Gunpoint Half-Life Half-Life 2 Half-Life 2: Episode One Half-Life 2: Episode Two Hard West Hotline Miami Hotline Miami 2: Wrong Number Inside Just Cause 2 Left 4 Dead Left 4 Dead 2 Limbo Little Inferno Lumino City Never Alone (Kisima Ingitchuna) No Time To Explain Octodad: Dadliest Catch Portal Portal 2 Postal 2 Retro City Rampage DX Saints Row 2 Shovel Knight: Treasure Trove South Park: The Stick of Truth Spore S.T.A.L.K.E.R.:Shadow of Chernobyl Stardew Valley Super Win the Game Undertale Wolfenstein: The Old Blood Wolfenstein: The New Order World of Goo