Always use commentary when you can, it falls under fair use. But always double check the terms and conditions from the publishers/developers on their websites. If they don't have any contact them. I almost recorded an early access demo for Beyond Two Souls to do a first impressions type video. I emailed Quantic Dream to be sure, turns out they don't even allow you to do videos that aren't commercialised. Dodged a bullet there O.O.