Portal 2 follows the player-character Chell after the end of Portal, in which she destroys the rogue artificial intelligence construct GLaDOS that ran the Aperture Science Enrichment Center where the game is set. In Portal's backstory, Aperture Science conducted experiments to determine whether human subjects could navigate dubiously safe "test chambers", until GLaDOS killed the scientists with a neurotoxin.
OS: Windows 7 / Vista / XP
Processor: 3.0 GHz P4, Dual Core 2.0 (or higher) or AMD64X2 (or higher)
Memory: 1GB XP / 2GB Vista
Hard Disk Space: At least 7.6 GB of Space
Video: Video card must be 128 MB or more and should be a DirectX 9-compatible with support for Pixel Shader
