Portal 2

Portal 2 is a puzzle game presented from the first-person perspective. Normally, the player, as either Chell in the single-player campaign or as one of two robots, Atlas or P-body, in the co-operative campaign, can move, look, and carry and drop objects. The goal is to maneuver the characters through a number of test chambers in the Aperture Science facility, traversing the chamber from the start to the exit.

Though the player-character can take some damage for a brief period of time, they will die under sustained injury and be restarted at a recent checkpoint; however, characters are equipped with "long fall boots" that absorb the shock of landing after a large vertical drop.

The player must figure out how to overcome seemingly-bottomless gaps, evade pools of toxic liquid, or avoid line-of-sight or even disable robotic turrets to safely arrive at the exit.