Coi is a modern programming language designed for building reactive web applications with high performance and type safety. It compiles to WebAssembly, enabling smaller bundle sizes and efficient runtime without a virtual DOM. The language supports composable components and fine-grained reactivity, making it suitable for various app types from dashboards to games.

The article discusses Celeste, a game that utilizes WebAssembly (WASM) to improve performance and accessibility in web-based gaming. It highlights the benefits of WASM in delivering smoother gameplay experiences and the potential for expanding audiences across different platforms. Additionally, it explores technical aspects of integrating WASM into game development workflows.