The Portal 2 Perpetual Testing Initiative DLC launched this Tuesday for free to all owners of the (PC/Mac) Steam version of Portal 2. This DLC enables gamers to create their own test chambers and share them with the world via the Steam Workshop. From where I sit, the DLC appears to be very successful, with over 14,000 user-created test chambers in the first ~12 hours of launch. I was excited to get my hands on this tool to see what it (and I) could do. This got me thinking about Portal as a series and why user-generated content is so necessary/appropriate for a title like this.