10 Things You Didn't Know About Portal
3. A Number Of Gameplay Elements Were Scrapped From Portal 2
Portal 2 is stuffed with imaginative gameplay mechanics, taking advantage of the crazy scientific world of Aperture Laboratories. From lasers to tractor beams, hard light bridges to oversized catapults, Portal 2 is a gigantic toybox filled with entertaining gizmos which the player can combine with their portal gun to solve even the most challenging of puzzles.
But did you know that a couple of testing elements were actually cut from Portal 2? A fourth mobility gel was originally planned that would allow the player and objects to stick to surfaces, letting you scale walls and walk on the ceiling. Valve dubbed it "Adhesion Gel". It's a novel concept, and it sounds fun on paper, but sadly it was scrapped because it made playtesters motion sick and was difficult to design puzzles around.
Another scrapped element was the Pneumatic Diversity Vent. These giant vacuum tubes could extend their powerful suction through portals, allowing the player to hoover up turrets and cubes.
They were cut from the game as a testing element, presumably due to their limited puzzle potential, but they can still be seen all over the game in behind-the-scenes areas, snaking around the facility like that old 3D pipes screensaver everyone used back in the day.