Downloading JARs

I'm trying to download this java applet so's I can play it offline:

http://dan-ball.jp/en/javagame/dust/

So I downloaded the .jar, and then in the same directory made an HTML file into which I copy-pasted the <APPLET> tag from the original web page. I also downloaded any .js files linked to by that webpage just in case.

But when I try and run the applet by opening the HTML file in firefox, it throws null pointer exceptions. What's going on here, /prog/?

>>2
This list seems biased. I played Super Mario Galaxy once and it was atrocious.

>>3
Same, except I played it more than once and it was atrocious each time.

Also, OP here still hoping for some answers.