Simulations of real world systems present the designer with a unique set of challenges. In entertainment products we strive to maintain the "illusion" of reality so as to nurture the meglomania in our players (the Calvin syndrome). In educational uses, however, we want to let our players "open the hood" of the model to view and perhaps change the underlying assumptions. These two approaches frequently conflict in the design of edutainment (yes, I hate that word too) programs. I will try to at least touch on the following topics:

• the intent of the program.
• maintaining the illusion.
• promoting empathy.
• granularity of interaction.
• time control.
• the use of sound.
• what's under the hood.
• collapsing and filtering of data.