> recently we had a particularly bad case: a customer sent us an approximately 1 GB project file which was corrupt, for a game already published to Steam, which they'd spent months working on. They told us all their backups were corrupt too... Predictably, WinRAR's repair tool produced a 1 GB ZIP file that contained nothing.

Thirty years of creating and storing zip files on every major and some minor OSes, filesystems, sketchy transfer protocols, and unreliable media make me think that the huge number of issues this company has with corrupted ZIP files has nothing to do with the format or with its customers' bad practices. I think their software might just produce bad zip files.