Hi OnemanVN,
thanks a lot for your quick reply. I am pretty sure you did your research about the german rating but I am wondering how some games/devs can pass with the rating logo I posted in my OP as that logo no way is the official logo the german USK issues for approved games. So I assume other devs just mark their store page as checked/age verified and Steam is ok with it.
This is the official USK rating logo (in different colours depending on the age rating):
I'll buy version 2.1 now from Itch.io. You should see my email address from te payment. It's a mail address finishing with @gmx.de. Just let me know if it works for you or if I need to send you somehow the full mail address.
Cheers!