GameStop’s digital distribution service, Impulse, now offers a few of Valve’s hits for download. This is the first time Valve’s games have been made available on a digital service outside of Steam.
Gamasutra says that Portal 2, Left 4 Dead, Half-Life and The Orange Box are now available via Impulse. You’ll still need to register the games through Valve’s Steam client, though. Hell, you might as well just buy them on Steam.
Think of the games being on Impulse as a wierd sort of link to Steam, bringing GameStop’s customers and their purchases to Valve’s service. It seems like Valve is not worried at all about their competition.