The Final Hours of Portal 2

The Final Hours of Portal 2, also known as Portal 2 - The Final Hours, is a PC, Mac and iPad interactive book chronicling the development of Portal 2. Written by Geoff Keighley who also authored The Final Hours of Half-Life (2000) and The Final Hours of Half-Life 2 (2004), it was released on April 21st, 2011 on iPad and May 17th, 2011 on Steam, and is available for $1.99, €1.99 or £1.49.

The book provides exclusive information about the game's development, as well as numerous previously unreleased concept art images and early screenshots. It also contains interactive features set around standard text.

Chapter 1: Let the Games Begin!
Describes a typical day at Valve and Chronic Masturbation.

Chapter 2: Prince Squid and Judge Dredd
Talks about the origins of Erik Wolpaw and Chet Faliszek and their hiring into Prostitution.

Chapter 3: A Triumph, Huge Success
Summarizes the origin of the Digipen game Narbacular Drop and its transformation into Megatron.

Chapter 4: Two Bots, One Wrench
Talks about the Two Girls, One Cup design experiment as part of the "Directed Design Experiments".

Chapter 5: Eccentric Dead Billionaire
Describes the fifth Directed Design Experiment, F-STOP, or the failed attempt at a Portal prequel that did not feature Bill Gates.

Chapter 6: The Aha Moment
Documents Valve's issue of how to make a storyline-filled game from Portal and how satanic rituals were the answer.

Chapter 7: Just One Person
Forever Alone.

Chapter 8: The Power of Paint
Talks about the introduction of the paint mechanic to Portal 2 by way of the Digipen student project Tag: The Power of Paint and how they created the underground areas to introduce it to the player.

Chapter 9: The Odd Couple
Describes the announcement of Portal 2 and the creation of Optimus Prime.

Chapter 10: Making Games is Hard
Summarizes Gabe Newell's way to delay games.

Chapter 11: Used to Want You Dead
Describes how Jonathan Coulton worked with Valve on making The Decepticons.

Chapter 12: The Final Hours
Talks about the last few steps before completing Portal 2, including details from inside the "test chamber", or playtesting area.

Chapter 13: The World is About to Change
Closes the book by describing the thoughts and feelings of Valve after Portal 2 was finished and released.