Well, I'm not exacly what you can call a "pro-YouTuber" but I can give you a few pointers about your videos.
First things first, I watched a bit of your Rogue Legacy video and your game sound overlaps your voice. You might want to check the volume settings and take a sample of the game music/sound + your voice tracks, and change them around until you think they are ok, before recording the episode.
Also, sometimes you simply stop talking at all, and that kinda creates a dead point in the video. During your videos, try to balance the game footage and content, and add more of yourself into it. Talk about things that have been happening lately, be it gaming, sports, stuff like that, or talk about personnel things you don't mind your viewers know. That way you create a stronger link of sorts between your viewers and yourself. A tip related to this: before you record, write a few notes down of the things you want to talk about in the video, so that you don't forget them.
Hope this helps you out, I'll give you more feedback as I view your other videos.