Okay the first page I landed on was the Feed tab, turn off the always redirect users to the feed tab and have your featured video set up on autoplay, you will gain extra views that way and in my opinion people are more likely to click through onto the others if the thumbnails are larger, so yeah, make sure the first page they see is the Featured tab the same as I have it on YTtalkTV, that is my own personal favourite and performs the best with my experience.
With your background I would remove any references to things other than your channel URL/name which is VANG1LF, mentioning the Sheepy stuff will really confuse people and could have them thinking that's how to find you when it isnt, I would only keep the sheepy stuff if its needed for a good reason. It would also be cool if the text was more opaque as I struggled to read it, you want this stuff to stick in your visitors head and struggling to read something will get on their nerves and not help them with remembering you.
In your Portal video I noticed you started up the game and were waiting for it to load, perhaps get straight to the action all the time by making sure youre already on the start screen. Your quality is fine for the Portal video but I would work on the audio, maybe make it not as loud by lowering the audio level in your editor, I dont know why but it sounds like its been amplified or something to me.
Im not too good at gaming videos but thats my few cents on what I have seen briefly
