The Portal 2 Authoring Tools include versions of the same tools we used to make Portal 2. They'll allow you to create your own singleplayer and co-op maps, new character skins, 3D models, sound effects, and music.

Here's what's included:
- Updated version of Hammer, the Source level editor
- Updated Faceposer
- Example maps and instances to help build new maps
- Updated suite of command-line compiling utilities