Even though I use the unrated patch, it still has mosaic, so can't move the mosaic ?

The "unrated patch" offered on GOG is just the R18 patch which means it will add some adult content usually not available.

However... for this game, the adult content is still censored, so it will not uncensor any content!

In order to be able to uncensor it you will need a uncensor patch which is called Demosaic patch and it is not offered anywhere except on the official "Nukige Nightclub Discord Channel", just look out for the Steam group "Nukige" and there is a link there. I am not allowed to post those links for obvious reasons.

In order to join the Discord some verification is required, no biggie... and the patch you need will be located at "Patches", right the first link there, which is leading to "Google Drive" with the description "Steam Patches". Just look out for the "Brianode" folder and inside this folder there is the uncensor-patch you will need. Simply unzip the "Demosaic Folder" inside your game folder, thats it!

Be aware: Posting links to any of those content is strictly forbidden and providing those content in any form on another place is as well strictly forbidden!

It is simply "to risky" for them... as we know already how many games has not been able to be become released on "official game sites" because of adult content... so it is in fact a threat to them.

Such a demosaic patch is not always available because in many terms the devs decided not to make it available at all, at no place... so consider yourself "fortunate". As this game is as well with good gameplay... a rare thing on many "Eroges" (Eroge = Japanese term for games with adult content).

Besides: GOG is not directly releasing a game because this decision is usually done by the publisher or dev. GOG is simply a store and storefront providing a platform for the games which are becoming "released", if the IP owner decides to do so, which is then "handled" and provided by GOG usually at the very last step.

GOG simply may decide "which game is able to become released there" as they are basically hosting and providing it, as a store and storefront. The IP owner usually does not want to provide censored games, but they usually feel worried their game might not become accepted on any given store, in a "non censored" condition, so they are usually censoring it. Sometimes there are uncensor patches available but not always, and they still worry some bad "side effects". It is kinda a challenge the whole matter, for everyone involved.

As, why GOG may not accept such games is because they as well may worry "bad side effects" usually done by the people not in favor of such games.