Both generally and specifically, the biggest pointer is a question: Why are you making this video? What is it about this game that made you want to record it and present it to other people? State your answer in the form of a video with Metroid: Zero Mission gameplay and there you go.
I don’t know anything about you other than your age, so I can’t imagine what type of person you are, what information you might be able to put into a video, how you want the viewers to see you, or any more useful attributes. That, too, is stuff you’d be putting into video form, but really, I think you just need to understand who you are, who you want to be, and how you want people to see you play games. Then do whatever comes naturally.