Valve still working on single-player games — and those Half-Life and Portal movies - Polygon
TF2/Team Fortress 2 Mapper's Reference - Valve Developer Community | Team fortress 2, Team fortress, Fortress 2
wickedplayer494 on Twitter: "A lot of Valve employees are fed up with scammers attempting to impersonate them (mainly off of the Steam platform entirely), so much so that numerous (but not all)
u]downloading Source Sdk Through Steam[/u] - Source Engine Valve Development Kit | Full Size PNG Download | SeekPNG