Portal 2 Review
Official Portal 2 Website - Blog
Steam Community :: Guide :: How to Create Good Logical Puzzles
Puzzle Creator - Portal Wiki
Portal 2 on Steam
Returning To Portal 2 – Waltorious Writes About Games
Portal 2 Peer Review DLC: fun, but missing the magic | Ars Technica
Pacing in Puzzle Games on the Example of Portal 2
Portal 2 Puzzle Maker: Indicator Lights - Valve Developer Community
Portal 2 improves brain training more than software designed for that, says science | Eurogamer.net
Portal 2 Puzzle Maker: Observation Room - Valve Developer Community
Steam Community :: Guide :: Using the Portal 2 Puzzle Builder
Steam Community :: Guide :: Using the Portal 2 Puzzle Builder
Testing, Testing: Portal 2 Puzzle Creator | Rock Paper Shotgun
Portal 2 - Wikipedia
Portal 2 PS3 Review - www.impulsegamer.com -
Puzzle Design in Portal 2- Creating a simple test chamber - YouTube
Steam Community :: Guide :: How to Create Good Logical Puzzles
Official Portal 2 Website - Blog
Portal 2 Review – ZTGD
Portal 2 Puzzle Creator : How to Make a Good Test Chamber : 3 Steps - Instructables
Portal 2 Level Design : new mechanic, multi puzzle | Seewon Park
