Title from cover

The official guide to Valve Corporation's Xbox 360 video game. The guide follows a new concept: the solution only gives away as much as the player wants to know. Thanks to a multi-layered walkthrough consisting of different levels of information, the guide lets players decide for themselves how much help they receive. From just a small hint right up to a complete solution -- everything is there. This guarantees a maximized gaming experience. Also included are an interview with the game's producers, previously unpublished concept drawings and artwork from Portal and Portal 2, and a comprehensive section on Trophies/Achievements, for all of those who wish to fully master the game

"Based on a game rated by the ESRB Everyone 10+"-- page 4 of cover