JavaScript - Lightweight, interpreted, object-oriented language with first-class functions
Project Anarchy - Project Anarchy is a complete end to end game engine and state-of-the-art toolset for mobile.
Allegro - Allegro 4 and Allegro 5 are cross-platform, libraries mainly aimed at video game and multimedia...
GDevelop - GDevelop is an open-source game making software designed to be used by everyone.
Qt - Powerful, flexible and easy to use, Qt will help you not only meet your tight deadline, but also reduce the maintainable code by an astonishing percentage.
Adventure Game Studio - Adventure Game Studio provides the tools to make your own adventure, for free!