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.
I'm sorry you're having a hard time with it.
Unfortunately I'm not sure what else to suggest either. I test-downloaded the file and it works fine, just to be sure. At this point, I have to assume it's an issue outside my ability to fix whether it is with Itch or your internet provider.
I'm really sorry I'm unable to identify or repair the download issue.
