Hello, I'm really happy that you liked the game!
Just like you, we used free assets from Ansimuz.
The sounds are from free-sound, and we find the music in the asset pack (Used by Ansimuz in demo, credit to Pascal Belisle, soundcloud).
The asset pack name is "Sunny land".
Ansimuz is on itch.io, take a look at his page ;)
We only are developer, sadly!