[KaktoR]

1. Unpack data.pak with "01_unpack.bat"
2. Compress extracted data ("data.pak_extracted" folder) with your tools
3. Zero extracted data ("data.pak_extracted" folder) with "03_zeroing_extracted_files.bat"
4. Reimport zero'd extracted data with "04_reimport_zerod_files.bat"
5. Compress zero'd data.pak with your compressor (ratio is 1% or less because the data.pak file is empty at this point)
6. Install the game with your installer (or extract archive files otherwise). After this point the extracted data ("data.pak_extracted" folder) is now like the original files again
7. Reimport extractred data with "07_reimport_extracted_files.bat"

Look at the data.pak before and after reimport zero'd files.

Original


Reimported zero'd files


If you compress the modified data.pak with 7z or any other compressor, ratio is extrem low (compressed data.pak from 91MB to 25KB).