You can play and show off whatever you want. I love older games and often check them out on YouTube so I don't think thats a problem. Currently you've only got 14 subs so the views won't be great atm, your latest video got 35 views though in a day so thats good.
I'd say keep uploading what you like, the viewers interested in that genre will watch and your subscriber and viewbase will increase. In the meantime you could make sure to share your videos on forums/twitter/facebook/friends/family/zoo animals, anyone you can really.
For example there is a forum called
Digitpress which has a classic game section, in which you can place links to your video play-through and reviews. That will always help to get viewers, as your already got the right audience as their viewing the forum page