The game is designed to:
Differences in individual ordering patterns (free will) result in the quantitative differences in game results. But the qualitative patterns are the same.
You might reflect at this point on what happens in the real world when such order-rate, and inventory oscillations are generated. The typical organizational response is to find the "person responsible" (the guy placing the orders or the inventory manager) and blame him. The game clearly demonstrates how inappropriate this response is--different people following different decision rules for ordering a generated oscillations.
"All of you who were not retailers, or who otherwise have not found out what the pattern of customer orders was, what do you think the customers were doing?"
Most people usually believe that customer demand was fluctuating because they believe that the system fluctuations must have been externally driven. Get each of them (other than retailers) to see that they assumed fluctuating customer orders.
This simple exercise of getting them to see how, contrary to their expectations, the internal system structure is completely capable of generating fluctuating behavior is the most profound lesson they can learn from the game.
In system dynamics we take an alternative viewpoint--that the internal structure of a system is more important than external events in generating qualitative patterns of behavior.

Most people try to explaln reality by showing how one set of events cause another or, if they've studied a problem in more depth, by showing how a particular set of erents are part of a longer term historical process.
The basic problem with the "events cause events" orientation is that it gives you very little power to alter the course of events. The focus on internal structure greatly enhances the possibilities of influencing the course of events because you are dealing with the underlying source of the process, not just trying to manipulate events.
"How do we deal more effectively with underlying structure?"