Portal

Action, Steam Achievements, Partial Controller Support, Single-player, Includes level editor, Captions available, Includes Source SDK, Commentary available, Remote Play on Phone, Remote Play on Tablet, Remote Play Together, Tradable

Link to the game in Steam

Portal - Gamescon

Portal™ is a new single player game from Valve. Set in the mysterious Aperture Science Laboratories, Portal has been called one of the most innovative new games on the horizon and will offer gamers hours of unique gameplay.