20 Video Games With Cut Content That Change EVERYTHING

Even though Portal 2 is considered to be among the best sequels in gaming, it didn't start off as a sequel at all. Stranger still, it wasn't initially going to utilise portals. 

In the beginning stages, the project focused on a photographic mechanic called F-Stop. Players could take pictures of objects with this device then place them into the real world, effectively "copying" them. The mechanic allowed for resizing, rotating, and repositioning captured objects, enabling players to solve puzzles by altering the environment in creative ways. Playtesters liked the F-Stop mechanic, but were disappointment by the lack of portals, encouraging Valve to make a more traditional sequel.

Though Portal 2 incorporated new elements, such as Propulsion Gel and Hard Light Bridges, there were other proposed concepts. Valve considered different types of portals that could slow down objects or alter gravity. There was also going to be an Adhesion Gel, which Chell could stick to, opening up all sorts of puzzle possibilities. Damage Gel was also considered, which would serve as an additional obstacle while navigating around turrets and pits.

Although these ideas were complex, they didn't necessarily improve on the puzzle flow, leading to their expulsion.