win64 indicates it is built for 64-bit Windows operating systems.
Save files from version 0.11 are likely incompatible with newer versions (0.15+ or 1.0) due to significant engine and script changes over the years. Lust-Is-Stranger-0.11-win64.7z
.7z is a high-compression archive format that requires a tool like 7-Zip or WinRAR to open. Key Considerations win64 indicates it is built for 64-bit Windows