Programming and control of the robot is what separates the great teams from the good teams. In only a few hours the robot can be programmed to move around the field and to play the game.
What takes the huge amount of time is to incorporate a wide variety of sensors and use that information intelligently. The ability for the robot to think and assist the driver and operator in playing the game is what makes a great team. The ability for the robot to act on it's own during the autonomous period to score bonus points is what makes a championship robot.
Programming is the critical thirds leg (design, construction, programming). It is a high pressure environment with changing requirements and an ever shrinking time window for testing.