Check out Procyon's[1] java decompiler. Another great tool would be CFR[2]. Never know when these might come in handy.

edit* mind if i ask what game it is? :)

[1] https://bitbucket.org/mstrobel/procyon/wiki/Java%20Decompile...

[2] http://www.benf.org/other/cfr/

This is really awesome, the sort of thing I love to see on HN! Thanks for writing & posting it.