Discover how Lion Shield LLC verified the viability of their hit city-builder Kingdoms and Castles in this 2019 GDC session. Learn about market fit testing, art style reworking, and player fantasy development from Peter Angstadt. Explore the importance of inventing design, using existing metaphors, and implementing simple primitives in game development. Gain insights into studio culture, the pitfalls of crunch, and strategic decision-making. Understand the marketing success through YouTube and community building via Discord. Delve into the development process of Kingdoms and Castles, from its inception to its release, and uncover valuable lessons for aspiring game developers.