The game Portal is developed by the Valve Corporation. It is the perfect puzzle game and has won many awards for its amazing gameplay and extraordinary theme. If you have not tried it, then click to play here. When the game has finished loading, you will see the menu with a gray background which sends out a dreary vibe. From the options you can adjust the sound and music level, the image quality and effect level. In the very first level, you are acquainted with your portal gun, also called the Aperture Science Handheld Portal Device (ASHPD). You will find your character in a glass chamber and your goal will be to find a way out of there. One you are able to fulfill this objective and get out the room alive, you will move on to the next level and be presented with another puzzle. There are more than 40 levels in the game.