Yeah, just like everyone has said thus far, really great serves, a lot of different variation and good spin. You probably do this more in a game, and have improved your serves, since this is an old video, but I would definitely say that you should try to put more emphasis on disguising your serves. I don't mean covering them up with your hand or something, but just making it so that before you contact the ball, and immediately after you contact the ball, the movements are all the same. Serving is important for the how much spin it has, but it is almost just as important for the aspect of surprise it gives.
Dan in his video about playing Ma Lin talked about this. Ma Lin's serves in terms of movement look nearly all the same, its just that at the instant he contacts the ball with his paddle, his lightning fast wrist flick is doing different things. Therefore the opponents reaction time to tell what type of serve it is, and what type of spin is very small, which in turn leads to mistakes if in that short time, the opponent makes the wrong decision as to how to receive the serve. And when we are talking about the higher levels of table tennis, where the amount of spin on serves are huge, even a slight mistake can put the ball either high enough or in a position to completely turn the point in a huge favor for the server.