Hyperlinks for the file downloads weren't implemented correctly. Files are unable to be downloaded. Only the option to download the full game is available.
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You don't "implement hyperlinks" with Itch; like every other filesharing site in existence you upload the files and they generate the download links. Also, if the full download is working then the download links are working.
If you mean that the Itch updater won't update then that's an issue you'll have to take up with Itch. I don't have any control over their proprietary systems.