Who doesn’t know Kelly Bailey by now?

He did all of the sound design for Half-Life 1, music and game sounds alike. Same for Half-Life 2, Episode One and Episode Two. His face was even used for a CG model of Gordon Freeman himself.

We don’t know if he did sound design for Alien Swarm, Portal, Portal 2, TF2, L4D or L4D2, but he did part of the soundtrack for Portal alongside Mike Morasky.

Sadly, it would appear that he has left Valve.