Good job!
I've watched all three of these now, and they are all great.
A few issues I saw with the last one were improved, such as the animation used for the Zerg.
Still, the only thing that could be infinitely better is voice acting. To me, everyone pretty much sounds exactly the same, which probably is true.
I love the use of sound though straight from the game, very great. Keep it up. The little bits of humor were a good relax from the action stuff as well, but remember to never overdo it.
And that's about it. Keep finding ways to improve the series, and these will end up becoming better and better.