05-16-2012, 12:04 PM
All I could really find was this page, scroll down to gcfsysd. It says that it can extract files from .fsys files from X Gale of Darkness. It seems to focus on sound data, although it may extract some kind of models from it, too. (Through pure coincidence, this is from the same site that I quite recently got an audio decoding library from. Funny.)
This thread might also help somewhat, although it's more about ripping .fsys files than opening them.
This thread might also help somewhat, although it's more about ripping .fsys files than opening them.