I always found the Display List in Flash to be a pleasant thing to work with.
http://www.stagexl.org/samples/
And you can look at some source code examples here:
https://github.com/bp74/StageXL_Samples
And StageXL also supports runtimes for Spine, Dragenbones, Flump, ...:
https://github.com/bp74/StageXL_Spine
https://github.com/bp74/StageXL_DragonBones
Especially with new things like the Flutter toolkit for mobile apps, it'll be nice to have something like StageXL for porting those games to browser or from the browser to apps, etc.
Dart gives me the feeling that it'll be easy to port my code to another platform later. Nice and simple, but plenty fast enough and with good lang features.
I'm on a Chromebook, and none of the performance demos seem to work... nothing renders or happens at all
Screen Management + Responsive Layouts + Material Design UI library + Spring Application Context (IoC/DI) + MVC/Commands + Physics + Google API + Facebook API + whatnot.
To kind of prove that the Dart2JS compiler is amazing: What you see comes in 230KiB gzipped.
Also make sure to check out the button to the upper right. If it does magic, you're on WebGL.