I think you didn't export it properly? This is the project file of the game (which is fine for the 'share the source code' challenge) but it's not playable.
You should go to export project -> HTML5 website
and then put the entire folder into a .zip file
upload that file here and that will be playable online
To make an executable file for windows/linux/mac go to export project - NW.js and that will create a folder for each operating system. (It requires a plugin but it gives you a link to download it)