This game runs off the half life 2 engine, will be released for PC and Xbox360 + PS3......
From IGN:
"But seriously, shizzle aside, the Portal demo blew our minds. In the demonstration, Newell walked us through the concept. I'll back up a step. If you've played or heard of Humanhead's Prey, then you know the game offers organic portals throughout a giant sentient alien ship. The portals are dimensional doors into different areas in the ship, and they're graphically and conceptually well implemented and work seamlessly. They're also stationery. In Portal, a seemingly independent game that ships with the PC version of Half-Life Episode 2, and the bundle of Half-Life 2, Episode 1, 2, and Team Fortress 2 on Xbox 360 and PS3, players use a tool that creates portals on the fly. Yes -- a gun that creates instant openings through walls that transport you in the bat of an eye to another place."