As far as I'm aware there is no issue with the game file as there have been thousands of downloads without issue over the last year. A download error is much more likely to be something outside my control such as a problem with internet connectivity, even itch.io.
The only advice I can give is to enable alternate download mode, which you can do if click the small link next to the download button. You will get a small pop up that allows you to do this.
Outside of trying this, I'm afraid I don't have any other solutions since a download error is likely being caused by something outside my control. Hope this method helps.
