Wow, the blog post was really well-written, containing lots of interesting points for non-physicists interested in learning quantum mechanics, and the game seems fun. And on HN the author encounters a bunch of dreary know-it-alls going on about how they don't like java applets for some reason (apparently it upsets their anal notions of security in their little laptop world.) Just open it in firefox, it works fine.

Unless you have a problem with running unknown compiled code, why not?

It's as easy as running '$ appletviewer URL'

Because having Java enabled for a browser is tremendously more risky than running a single application of unknown code.

As RobSis noted, you don't have to enable it in your browser, you can use appletviewer to run individual applets without the browser:

    $ appletviewer http://tropic.org.uk/~crispin/quantum/

And also, moderns browsers allow you to have the plugin installed, but disabled unless you activate it on a specific page.

Modern browsers... except Google Chrome, which has at least 40% market share.

Google Chrome does not support applets in any way since the deprecation of NPAPI.

I accidentally had appletviewer.exe it from the JDK, however the applet is served over http. I do appreciate this because I'd accidentally turned off HTTPS Everywhere and hadn't noticed (in weeks I suppose).

I think I'm not the target audience, I hope OP finds some good physicists to show this to :)