The cake is a lie. You better have your companion cube and the crazy soft 100% Portal Test for That 30 Single T-Shirt close by because you'll probably be gritting your teeth as you make it through Aperture's array of 'accidents'. You know, for science-y type folk they really didn't care all that much about their test subjects! Are you a fan of bending the rules of a physics with a portal gun? Are you a fan of shirts? You should get the Portal Test for That 30 Single T-Shirt but be wary of GLA-DOS!