 Additionally, Valve had started development of Source 2 at the time of "Episode 2" release; as developing "Half-Life 2" and the original Source engine simultaneously had created problems, Valve delayed development of a new "Half-Life" until the engine was completed, by which time they were experimenting with virtual reality.In 2016, "Half-Life" writer Marc Laidlaw left Valve.Laidlaw said he had intended "Episode Three" to end the "Half-Life 2" plot arc, at which point he would "step away from it and leave it to the next generation".