Experimentation is a cornerstone of successful game development and live operations, enabling teams to optimize player engagement, retention, and monetization. This article provides a comprehensive guide to implementing experimentation in gaming, structured around the game development lifecycle and the marketing mix. From pre-launch concept testing and prototyping to post-launch personalization and LiveOps, experimentation plays a pivotal role in driving innovation and adapting game experiences to diverse player preferences. Gaming presents unique challenges, such as highly engaged communities, complex interactive systems, and highly heterogeneous and evolving player behaviors, which require tailored approaches to experimentation. The article emphasizes the importance of collaborative frameworks across product, marketing, and analytics teams and provides practical guidance to game makers how to adopt experimentation successfully. It also addresses ethical considerations like fairness and player autonomy.