Tapping this button multiple times is not good. It creates several documents in an undefined state.

There is a slight delay from tapping the "Create Document" button until the document have been fully created in the file system. A blocking mechanism is needed. That stays invisible if the document gets fully created within a reasonable amount of time. Otherwise a HUD is to be shown. Or an error

The CC-BY license is a good choice for the assets for this project. And as long as there is only a single artist whose assets are involved, a generic crediting message is enough.

The problem comes in if multiple additional artists starts contributing and/or people would start derivative works of the assets within the project, for example recoloring/remixing tiles to extend the tileset. There sh