Just catching up with the most recent two vids.

Vincent didn't bring you your Mega-All materia because you foolishly jumped past said materia at 26:21 and 26:28. You have to quickly grab it before it auto jumps you. Also, the save crystal won't work on that screen immediately preceding the descent towards Sephiroth. You'll need to go back a screen to use it.

Can't believe this has nearly finished!