Portal: First Slice is absolutley free and includes the first 11 levels! About the Game Help yourself to a generous, 11-level serving of Portal: First Slice, the official demo for the game that challenges you to think with portals. The winner of numerous Game of the Year awards introduces you to the test chambers at the Aperture Science Enrichment Center, where you'll learn to solve physical puzzles by opening portals to maneuver objects, and yourself, through space. To install, click here! For more info, click here!