Generative Artificial Intelligence (GenAI) promises to democratize many creative endeavors, from art, to music, to writing. However, video games are an underexplored field for GenAI given the highly multi-modal and interactive nature. In this work, we present a case study game-jam-style game development process (performed over only a few days!) making heavy use of available GenAI tools (as of October 2024) to create a game called Plunderwater: Sunken Treasure, a title selected from among GenAI suggestions. We share our impressions of what worked well and what could use improvement, and hope that this paper will serve as a guide for GenAI tool developers to focus on the highest impact future improvements and as a starting point for future GenAI for game development benchmarks.