This article explores the practice of environmental storytelling in open-world games, emphasizing its role in creating immersive and engaging player experiences. It defines environmental storytelling as a method that uses environments—through visuals, sounds, and interactive elements—to convey narratives indirectly, allowing players to deduce stories via exploration and deduction. The article breaks down four key approaches: evocative spaces (triggering player memories), enacting stories (providing stages for role-play), embedded narratives (scattering clues for players to piece together), and emergent narratives (where player actions generate unique stories). It offers practical advice for designers, including techniques for constructing believable worlds (real-world research, high-concept integration, timeline deduction) and the importance of 'less is more' through resource reduction and narrative 'white space.' The piece also discusses dynamic scene staging, emotional manipulation via visual design, and collaborative production methods for scaling narrative content. Finally, it delves into interactive narrative design, focusing on embedded (fragmented) storytelling and emergent systems that give players agency to co-create stories. The overarching message is that environmental storytelling, though demanding, is a powerful tool for deeper player immersion and should be a collaborative effort across game development disciplines.