Godot Engine - Feature-packed 2D and 3D open source game engine.
DragonRuby Game Toolkit - DragonRuby Game Toolkit is a commercial-grade, yet beginner-friendly, 2D game engine.
MonoGame - MonoGame is an open source implementation of the Microsoft XNA 4 Framework.
RPG Maker - Make your own PC game with RPG Maker. Our easy to use tools are simple enough for a child, and powerful enough for a developer. Try it free today!
DragonRuby Game Tookit - Tiny, fast and cross-platform, 2D game engine in Ruby.
Blacksmith 2D - Black is a highly optimized 2D framework for web, mobile games, and playable ads.