What's on your mind?

[Kirito]

The use of pixi.js has a lot more to do with when they started development of the engine, and the fact that pixi.js is one of the most feature stable libraries out there. Many other classes have a tendency to lose compatibility between versions, and for something like a RPG game engine that's intended to be used and re-used over and over in an LTS ( Long Term Support ) style application, you don't go with the bleeding edge, or even necessarily the simplest, you go with the most consistent library available in order to reduce your support overhead. Especially if you're making a sub $100 game engine.