Since somebody took an interest in my year-old post mentioning that I looked at that game (and found its resources not interesting enough), I’ve made a quick and dirty unpacker for its compressed files. You can grab it here.
It is based on lhasa, which is a LHarc/LZH archiver that I could easily extract code from (I considered supporting it in na_game_tool properly but decided that I have no desire to write LH1 unpacker, even with many references being available). Essentially I ripped out LH1 decoding code from it, made it stand-alone and added a small driver to open and unpack JFX1/JGF5 files.
Compiling executable should be as easy as using C compiler on it (I repeated instructions in the beginning of the file just in case). For that only guy who cares (if he still does and actually sees this post)—happy hacking!