old thread, new informations :)
for the people interested in the encryption and the compression adopted in this game series I have written a quickbms script (is required quickbms 0.3.10 to use it!) based on the reversing performed today:
http://aluigi.org/papers/bms/stalker.bms
seems that only STALKER Shadow of Chernobyl used that "useless" encryption of the information table while after having scanned all the files of these games I have found no archives containing compressed files (because the archives have both a compressed and uncompressed size for each file) so contact me if you have one of them
in my opinion it's interesting to notice that the game uses a compression algorithm very similar to the not-much-known LZAH, but I was too lazy to reverse it and finding the differences so... I simply dumped it :)