It's an applet that requires Java 7. Make it not an applet, or remove the dependency on Java 7. And nicking someone else's art without attribution ...
Hmm thought I copy and pasted the entire thing when I reposted. It had the attribution as you call it for the creator of the graphics. Let me fix that.
If you really want some feedback - this is useless to me (and most other people I suspect). It's highly dependant on some 3rd party sprites that you admit you ripped from elsewhere and haven't included a source or license for.
3rd Party sprites? Not sure what that means. The sprites are not loaded else where but from the jar directly. You want me to post the source too? Not really understanding your sentence structure.
don't steal other people's art
The Famitsu site where the sprites came from advertise them as free and the tool used to make them is free as well, but web based and on a very slow server. This program takes care of the slow side of things.