We use cookies on this site including to improve its functionality and to record how you use our site. The collection’s other titles aren’t too shabby either: Portal takes gravity-based puzzles to the extreme by equipping the player with the Aperture Science Handheld Portal Device (also known as the Portal Gun), which places two portals for objects to pass through, while Team Fortress 2 continues to go from strength-to-strength thanks to the introduction of custom gear and well-balanced team combat.