As someone using D3.js a lot (even for a puzzle game) - what is the benefit of using Two.js? Jumping between SVG and Canvas? (But then, is it worth the price of reducing possibilities to circles and squares?)
You can do quite a bit with "circles and squares". Two.js focuses on Path drawing and has robust SVG interpretation for complex vector shapes.
I've found the portability to be fantastic. For instance http://patatap.com runs svg on iOS and canvas on Android. Two.js makes it simple to run either on the fly.
