Your vocal performance was a noticeable step up from last time, but you still suffer from a fuzzy mic, which lowers the overall quality quite a bit. I'm still against the powerpoint idea, there really doesn't seem to be anything gained by keeping text on the screen at all times that can't be done by using your on-camera presence combined with a prepared visual aid at the end of the explanation. I'd also recommend having everything that you're going to be using already open when you start, that way you don't have to spend ages hunting through your desktop to find thing x, which just makes the whole process a bit smoother and a bit more professional.
I personally would prefer if you didn't have to load a demo everytime you wanted to use a tf2 play to illustrate something. What I think would work better is if you recorded the segment you wanted to show earlier, be it with fraps or dxtory or lawena, and you bring up a video file instead of tf2. It'll be a little more prep work, but it'll eliminate the load time/demo hunt that you currently have, along with minimising issues with crashes. I might record a 2-3 minute segment later on to illustrate what I'm talking about, and just so you can see how much cleaner and professional it can look.
Edit: done: http://youtu.be/zr5EKhary0I