Heide Park is a bit lucky as the latest laws don't apply for them at the moment because the relevant numbers are not over the threshold in their government body. I think the region of every other German park except for Hansa-Park would be over that limit and thus the parks would not be allowed to open. For Heide Park this can change rather quickly, as well. The numbers only need to be above the treshold for over 3 days and they would have to close. The case they won was against restrictions in lower saxony but the new law on a federal level should still apply.