Aside from individual save slots, the game creates a "System Data" file to track unlocked extras like The Mercenaries Assignment Ada 3. Technical Papers or Essays Reverse Engineering: There is a well-known technical paper mentioned in the book Hacking the Xbox
A Guide to Save Data in Resident Evil 4 (GameCube) The 2005 GameCube release of Resident Evil 4 Save Data Resident Evil 4 Gamecube
: Beat the main game once; available for 1,000,000 Pesetas in New Game+. Aside from individual save slots, the game creates