Well, as you know, a web server of some kind if required to run HTML5 applications and games. You'll need some sort of lightweight web server to run without internet access.
Good news is that Python with the SimpleHTTPServer module can do the trick, either with it installed locally on the system, or a portable version (dependent on OS)
In a terminal / command prompt, set the working directory to the root of the project, and execute this:
This hosts a simple web server on port 8080, which will run the project locally on the system, without the need of a dedicated web server. It simply requires Python and the SimpleHTTPServer module (I think is included with Python by default)
python -m SimpleHTTPServer 8080
As far as making this easier for the user, you can write a shell script (.sh) for Unix-like (Mac/Linux) or a batch script (.bat) for Windows that would only require a double click.