Core resources are in the .dat files master.dat and critter.dat. Patch data is in the files patchXXX.dat (see p. 3). Saved games, modified files and music are in the directory \FALLOUT2\DATA\. There is a standard directory structure, in which the game is looking for its files (it is similar for master.dat, critter.dat, patchXXX.dat and directories \FALLOUT2\DATA\): Notes: Paths to the music are stored separately in fallout2.cfg (it is not stored in DAT- files). Those files also include worldmap.dat games, which creates the game itself and writes in the first accessible roots (see p. 3).