I am very pleased that you liked it. 😍
The whole project is open source including all my sprite additions. https://github.com/puppetmaster-/vollmond
Pull requests are very welcome. 😉
If you have PyxelEdit I can even give you the original tilemaps.
I really want to extend the project and maybe add some ghosts and slimes, music and sound effects are also missing.
I even had the idea to buy the Dream Catcher Tileset and create my own game based on the same style as Vollmond.