Yes a previous version was built on canvas2D. For simple things such as a couple of objects moving across the screen it works great. As soon as you start to do fullscreen "camera" movements performance starts to suffer. All images and paths need to be uploaded to the gpu every frame. Maybe the browser optimizes some things but in my tests it was not enough.
The WEBGL renderer in this project is built from scratch because none were available that support SVG and were small enough for regular web pages. It allows me to upload paths and images to the gpu making fullscreen animations a lot more smooth.