You're probably missing the following files:
app.js - js code of the application
style.css - describes how it's supposed to look
/data/Archive.zip - file with default parts and configuration
FileSaver.min.js - lib
jszip.js - lib
They shoud be placed next to index.html.
Browser will prevent the app from using those files though - there might be some flag or option for that but it's inherently insecure.
Easiest solution is to run a local server.
On Linux something like `php -S 127.0.0.1:3333` would do. As for Windows: I've just found this list and there is one Windows solution there at the very end but I've never used it.