Portal 2

Just like in the first game, the gameplay is based around portals. By shooting a starting portal and ending portal at suitable surfaces, certain uncrossable gaps can be bridged. Just like in the first game, there are also many test chambers where puzzles need to be solved, using cubes, turrets, platforms, and special portal tricks to gain a lot of speed. GLaDOS makes a return to tease Chell and she plots revenge for her destruction, but there are a large number of twists that make her role very different from in the first game. Chell receives help from Wheatley, a small robot who opens entrances for her and provides witty insights about the environment.

New elements to the sequel's gameplay include light bridges, laser redirection, and paint-like gels. Gels provide extra speed, a jump, or neutralize the effects. They can also be used with objects such as cubes or turrets.

The game’s two-player cooperative mode is entirely new and features its own entirely separate campaign with a unique story, test chambers, and two new player characters (Atlas and P-body). The PlayStation 3 version incorporates some elements of the Steamworks toolset and allows for cross-platform games against PC players.