As with all Lego sets, The NXT has many parts that all fit together. But with the NXT you control it without using your hands all the time. By connecting Lego Technic pieces with an Lego "robot" or brain which in turn is attached to the motors and sensors which are attached to the Lego pieces creating in it's self a Lego robot.
But as with all robots this robot has to be controlled and programmed. In specific robots like Robosapians you control them by using a remote control to make it do what you want it to according to what the designers wanted it to do. Since you design what it can do you also can make it do what ever you want it to. The possibilities are endless, only stopped by the amount of sensors you have and the size of your Lego collection.
And as always PLAY WELL!