Excellent video. In the past, I have also got feedback that I sounded boring. I think the trick is varying your tone - Once I starting doing that I noticed students were more engaged. At the very beginning of the video, you speak in a monotone. You want to think about what makes you excited about 0 A.D. A lot of people probably don't listen more than like 2 minutes into a video, so you want to grab their attention in the beginning.