Why can't you buy it?
I think Itch.io had problems with the game content. You can buy it on Ci-en or wait for the official release on DLsite. You can also kinda buy it on fantia but visa and mastercard cards are "temporarily suspended" whatever that means.
You can buy it on ci-en or fantia. Alternatively, you can wait for the dlsite version to release. That will release in june 28th, nor far away :)
