Eccentric what? See the engine repo here for details.
These demos rely on npm, and by extension, node to download the tools that you'll use when compiling them from source.
How you do this varies between platforms, and there may even be different options on each platform. For example, on Mac you could install with homebrew (https://brew.sh), or download the software directly from the npmjs website (https://www.npmjs.com/get-npm).
Choose the method(s) you're happiest with, and once you've got the required parts in place, for each project you create ensure that you run
- npm install eccentric-engine
- npm install --save-dev webpack
- npm install -D webpack-cli
then, to pick up any stragglers, run:
- npm install
and if everything goes well, you'll be all set and able to run the compile.sh script for each demo project should you wish.