For newer and smaller gaming channels, starting off shorter may be a good idea. New potential people to sub may be put off by watching longer videos on smaller gaming channels. Larger more popular gaming channels offer more promise of entertainment given that they have more subs. ("Tons of subs? They must be good!") Rather, with smaller channels, new people have to take that initial "risk" of discovering if you're worth it.
With that said, max ten minutes to start is probably best. Try to keep things as interesting and engaging as possible. For your specific question, I'd say at /least/ two videos. Three or four would probably be better though.
(As a suggestion for future videos, based off the video on your main page, I would turn down game audio so people can hear you better. After all, what's the point of adding commentary if people can't hear you?)
