The development team tell us about this game engine: Phaser is free and open-source and always will be. To be better understood, the development team put a lot of examples of source code and online output on the official website. If don't want a github cloning, or setting up a local web server, you can run phaser in the cloud. You can test it with shaders, games created by developers. I did not find a YouTube channel, but the internet is full of tutorials for this javascript game engine.
