Thank you very much. In the game I downloaded here on Itch.io there are indeed still 30 levels. And they are the same as the ones you provided the solutions for.
However when I look into the mis_data\levels directory I see 51 levels. So to me it shows as if 21 forgotten levels are still there to be discovered? I think the data.txt has something to do with it? Only 30 levels are mentioned in that file.