It also lets them take some risks. For example, in the next episode of "Half-Life 2" (due in the first quarter of next year) Valve plans to kill off one of the franchise's regular characters.

Making such a move, particularly with characters that have become beloved in a major franchise is a risky one. But Newell said by introducing such a shocking twist, it can help the "Half-Life" story from becoming "just another watered-down serialized narrative."

"I think we want them to care about these characters and want them to trust that we're doing something smart with these stories," he said. "We want them to be genuinely be worried about the characters, so you won't think 'Well they won't do something to these characters, because they're too important.' If nothing matters, then nothing you do matters - and you're moving away from being in a world and back to being in a shooting gallery."