I am not sure if I can answer your question directly, but I will give my point of view. Bear in mind that I have not seen your previous videos, so I cannot give you any pointers there. You really want to sell the story, characters and world. Give some sort of literary analysis of its world and characters, something a little in depth and insightful. I am sure someone has probably already done something like that on Gamasutra, or maybe try browsing through Critical Distance for ideas. The opposite might be to try and think like an advertiser and that Shenmue's world is a holiday resort, why would someone want to 'visit' Shenmue? Another thing to consider is spoiling viewers. I have found myself spoiled for games like (majorly spoiled) Bioshock Infiinte and (minor) Zero escape, but the twists that I knew of made me want to play those games sooner rather than later. Obviously, be careful of the spoilers, or stick them near the end of the video with a warning.
I think it is incredibly difficult trying to sell the game mechanics due to the game's age and the fact that a person can be easily turned off by the wrong choice of language. Selling a person on game mechanics is really Suzuki's job on this one, and the best way is through a gameplay demonstration of some sort (I am not suggesting he do this, or that it would be a tipping point for me, I am just thinking hypothetically). If you really have to try to sell the game mechanics, you should use game analysis blog posts and journals as a reference, rather than video game reviews. Personally, my reasons for why I might back the project with a little money could be summed up out as a sense of charity. That, and the asian environments look like something that I would love to explore. I hope what I said to you can help, although I fear it may not be the answers you were looking for. I might not be the right man to pander to.
EDIT: Geography screw up
