The next time someone indignantly asks 'well what has Valve done that's earned them so much trust and goodwill towards Steam vs. [insert dd service here]' link this thread. The music release is already making my weekend a good one.
Nice! The original co-op puzzles were pleasantly challenging. I hope these follow suit. Also, the thread title is slightly misleading. It makes it sound like the original co-op is going to be free by itself.