Hey, thanks for the kind words and good luck with your own project! :)
I make CK using Koikatsu (available on Steam) which has no official licensing agreements but the parent company has publicly stated that they're happy for indie devs to use their assets (and have even defended devs against their own distributor in the past!). This means you can't put your game up on Steam if you decide to go this route, however - just something to bear in mind!