This document discusses game prototyping. It explains that prototypes are either code-based or content-based. Content prototypes using artwork and storyboards are best early on when the concept is unclear and open to changes, while code prototypes are needed later to test specific mechanics through interaction. Prototypes are not meant to be polished or address multiple issues, but rather answer focused questions cheaply to reduce risks and clarify the game design before full production. The talk encourages using prototypes to decompose ideas, experimentally test assumptions, and establish shared understanding within a development team.