However, I have to disagree with the whole premise of this program. There is absolutely no way anyone should ever attempt to learn any self defence techniques from the kinect system. That is just plain ludicrous. Even some real word self defence classes I consider to be a bit dubious, as no one should be attempting any of these techniques unless they really know what they're doing.
In self defence situations, overconfidence is an extremely dangerous trap - running away or screaming for help is usually the best defence. If you think you can perform a technique, and it goes wrong, there is a much more significant risk of you being harmed. The point being that I can almost guarantee it will go wrong if all you use is this kinect game.
Actually I think this is bordering on corporate irresponsibility by Microsoft. I mean listen to this trailer.
The woman says "self defence made me feel more confident...". But she is a black belt in karate! She doesn't mean "self-defence the kinect game" made me feel more confident, but is being deliberately ambiguous to mislead people. I should basically stop there before I go on an extended rant about how advertising (which is deliberate manipulation) is harming society. This is just an example which is actually dangerous.
In short do not buy this game. If you want to learn some tai chi (rather than self-defence) using kinect, I recommend you try "Your Shape Fitness Evolved".