The half life games were just okay.
They don't really have that deep of storylines or the characters, so I don't think that being inside the world of half-life would make a show better than being its own thing.
The best things about them were the way that you could move/interact with items in the world with the gravity gun, how a lot of the playable areas felt like they were places and not sets designed for a video-game, and that the orange box contained portal.