Torque2D
A completely free, open-source, 2D game engine
...It delivers a flexible and high-performance C++ framework that supports cross-platform development for Windows, macOS, Linux, iOS, Android, and the web from a single codebase, allowing developers to target a broad range of devices with minimal changes. The engine includes essential components such as a batched OpenGL renderer, Box2D physics integration, OpenAL audio support, automated asset management, and sprite and skeletal animation systems that simplify bringing characters and environments to life. With a modular project structure and support for object persistence using TAML, developers can build complex games with reusable systems and clear project organization. ...