David developed telecommunications software in Boulder, Colorado before he came to Valve. During his time here he's been a programmer/designer and cabal lead on Half-Life 2 and Half-Life 2: Episode Two. He has also worked quite a lot on our Hammer level editor over the years. A fan of recreational physical suffering, David goes rock climbing in his spare time. He has dragged many a pale and shaking Valve employee along on adventures in vertiginous terror.