Portal 2 has sold more than 4 million units worldwide since its launch on April 18, 2011, and Valve is slowly but steadily (mostly slowly) supporting it with new content, such as today's batch of DLC, the Perpetual Testing Initiative. The Perpetual Testing Initiative offers players a map-editing tool, which looks a lot like this, so fans can make testing chambers to rival GLaDOS'. And make maps shaped like penises, probably.

The map editor in today's DLC is accessible for new players, yet robust enough to satisfy hardcore ones, Valve tells NeoGamr. Valve's first attempt at fan-made maps, the Hammer editor, is tech-heavy and complicated for most people to get a hang of, most likely because it's Valve's in-house map creation tool - still, players have created more than 400 maps with Hammer. However, without a standardized way to share the maps, most of these have gone unnoticed by the larger community.

The Perpetual Testing Initiative's puzzle maker allows users to export their creations in Hammer's native format and continue building with the more powerful tools, if they so choose. The simple map editor is "incredibly powerful for all of its simplicity and can easily reproduce pretty much every puzzle from Portal 2," Valve said.