Portal is known for setting the standard for modern 3D puzzle games. The gameplay revolves around the ability to shoot out portals which can be traversed in both directions. It is a simple concept yet the game pushes what is possible with it to the limit. Not only is the gameplay well balanced but you also have an excellent story told through GLaDOS, the voice of Aperture Science. There are many moments where the story becomes your own, especially during the unforgettable climax.
When you start a new game you find yourself trapped in a small room. GLaDOS starts to explain that you're about to start series of test when finally a portal spawns to let you out. Its clear from the beginning that something isn't quite right, aside from the incredibly deadly tests that is. GLaDOS appears to have some glitches and some of the test have openings in the walls. At least while you're trying to solve the puzzles GLaDOS will keep you amused with her ridiculous statements. She is very blunt in her descriptions of the dangers you face and occasionally has even more off-the-wall stuff to say.
To make your way through each test you'll have to utilize portals. There are two different color portals and only one of each can be available at the same time. Not only can you move through the portals but so can objects such as the weighted cubes and energy balls. You'll need the cubes to hold down pressure plates while the energy balls will have to be redirected to power various equipment. Also you will carry your momentum through the portals making it possible to jump and fly to areas you couldn't otherwise access.
After you finish the story there is still some stuff to keep you busy. The highlight is the advanced versions of each chapter. The advanced stages are all similar to the normal levels but there are a number of changes made to make them much more challenging. Also there are separate medals to earn in each stage for completing them with the least amount of portals, steps, and time. Should you wish to learn more about how this clever game was made there is a commentary mode available where multiple developers discuss the game as you play through each stage.
There are many good reasons Portal has such a famous legacy. The unique mechanics combined with the finely tuned learning curve makes for a very rewarding exercise. GLaDOS's has a wonderfully dark sense of humor and the contradictory attitude of the turrets is equally amusing. Portal is such a clever game that the accessibility goes way beyond just puzzle game fans. Any gamer looking for a unique experience is bound to have fun making their way through the Aperture Enrichment Center.