Well.. are you asking about launch dates or actual time spent with your fireteam? I assume you mean actual time spent in game and that would depend merely on your fireteam composition and the skill and gear with each person. It'll be difficult at first but I would expect the first few weeks it may take an hour or a few for a full completion if you can figure out the mechanics of the fights. There will be puzzles or so what has been hinted via the reveal trailer. Hope that answers your question, guardian.