Urho3D is a free lightweight, cross-platform 2D and 3D game engine implemented in C++ and released under the MIT license. Developed by Lasse Öörni
License: Open Source
Unity is a versatile and widely-used game engine with extensive resources, making it suitable for both 2D and 3D games across various platforms. In contrast, Urho3D is a lightweight, open-source engine favored for its performance and customization, particularly for smaller projects.