Within your categories: try using 'ORDER BY Rating DESC' or something
Also, your "So bewerten wir" doesn't tell what (how many points) it takes to be assessed "sehr gut" and so on. Might add to the transparency to have a rating range next to the heading of the lists like this:
Sehr gut (XX-YY Punkte)
In dieser Kategorie sind Sites verzeichnet..
like the simple design but hate not being able to tell what's a link and what isn'T without hovering...
Lastly: Would be really great if you could manage to have a direct link to the sections of the sites for the content categories. Eg, If someone clicks on "Fonts" to see sites with Fonts, see if you can have links to www.gotfuturama.com/Desktop/fonts
and so on. I know that this is takes some effort, but it would greately enhance the usefullness of the category view.