Hi, I had the same problem when trying to download the game but i found a work around. You can download it from the itchio when its opened in your browser, it will take a while but it will eventually download. After that open your downloads and right click on the Cinderella Phenomenon and then select Extract all. This is just because the game is a compressed file format. Thats how I got it to work for me at least. Hope it works for you too!
Edit: Also you will have to open it directly from your computers downloads, somewhat inconvienient but a small price to pay to enjoy this wonderful game.