It's a project that wants to push further than shadertoy. Here from the project documentation:

My goal was to make something similar to Shadertoy but with some extra features. Having a fixed and simple set of functionality always helps in the creative process to focus on the goal itself rather than on the several methods available to achive the goal. Therefore i didn't want to overdo it with new functionalities and only implemented features i was missing most in shadertoy. Some basic main shadertoy functionality is there, but some features are missing.

Shaderoo is based exclusively on WebGL2, so WebGL1 is not enough (unlike shadertoy, which has some WebGL1 fallbacks). check webglreport.com for compatibility.

Shaderoo uses Ace as web-editor. See here for the keyboard shortcuts.