Portal

About the game

Portal is a first-person puzzle game developed by Valve and released in 2007. The game takes place in the test chambers of the Aperture Science facility. Players control the silent protagonist Chell, who must complete a series of tests supervised by the artificial intelligence GLaDOS. The player's main tool is the Aperture Science Handheld Portal Device, which creates two linked portals on flat surfaces.

The portal mechanic forms the foundation of all puzzles. Players must understand the laws of conservation of momentum: entering a portal at a certain velocity causes Chell to exit the second portal at the same speed. This allows solving tasks that initially appear impossible — such as crossing a vast chasm by building speed through a falling loop. Each new chamber increases the complexity with energy orbs, acid pools, turrets with childlike voices, and weighted buttons requiring special cubes.

The narrative develops through GLaDOS's voice messages, which initially sound friendly but gradually reveal a sadistic nature. The computer promises Chell cake as a reward for completing all tests, but the final chamber turns into a trap. The second half of the game takes place outside the test rooms — in derelict maintenance corridors showing signs of previous test subjects' rebellion. Portal was released on PC, Mac, Linux, PlayStation 3, Xbox 360, and Nintendo Switch.