MIT lecturers Philip B. Tan and Jason Begy take Lecture 19 of CMS.608 Game Design through the logic of simulation design, asking how a designer decides which features of a real system to model, which to simplify, and which to leave out entirely. The session uses examples like September 12, a political simulation game about retaliation and collateral damage, Every Day the Same Dream, and PETA's Super Chick Sisters to show how a game's abstractions carry an argument, not just a mechanic. Paul Starr's essay on policy simulation games grounds the discussion of what gets lost when a messy system becomes a rule set. The class works toward practical ground: generating design ideas for the students' next assignment by treating abstraction as a deliberate choice rather than a technical limitation.