ONE (Unity) is a cross-platform game development engine created by Unity Technologies. It allows developers to create 2D and 3D games, simulations, and other interactive experiences. ONE provides a user-friendly interface and a wide range of tools, making it accessible for both beginners and experienced developers. The engine supports multiple platforms, including PC, consoles, and mobile devices, enabling developers to reach a broad audience. ONE also features a robust asset store, where users can purchase or share assets, scripts, and tools to enhance their projects. This versatility has made ONE a popular choice in the gaming industry.