Your channel looks pretty good with the uniform thumbnails at the top, my only real issue with them is that some of the really nice detail on them is so hard to see, just because of how small it is. It's really, really nice, but it is so hard to see, some people might glance right over it, which just kind of wastes the effort you put into it.
Moving onto the banner, it's nice, but it is kind of plain. If you had a logo, then it wouldn't be a problem, but it has a motto, your name, and then a call to action. I think it would greatly benefit from some of the detail and designs you put into the thumbnails. I also think it is a good idea to keep that call to action (Like, comment and subscribe) in the banner, because looking into how people feel when they see the color red (The psychology behind it): "Red is energizing. It excites the emotions and motivates us to take action." So the combo of call to action and color use is really good.
Looking at the videos, you have some pretty good commentary. I only suggest you either turn down the game volume, or speak up. In your latest witcher 3 video, there were several moments where it became hard to hear you over the game.
All in all, your channel does look pretty good, and I can see how you got so many subs.
I hope this was helpful, you're awesome, have a great day!
