Starting off doing older games is difficult, especially old games that aren't yet considered old enough to be "retro." In your case, a game that is over a year old probably isn't getting searched for that much anymore, and most of the viewers for that game probably have already chosen their favorite YouTubers for it. If you're goal is to grow, I would suggest doing a very new game (like no more than a few weeks old) or better yet, plan to do a game that you feel you will like, that hasn't been released yet. When it does release, smash out some quality content for it as soon as you can, and incorporate the best SEO that you can into it's tags, title, and description.