There is no "top download button" on the top there only is a button that wants me to pay 19,99, despite I already paid on Humble. Below there are explanations on how to download the assets one after the other, but that is definitely not what I want. So I still see no option to download the complete Humble bundle.
Edit: I found a download button, but that only leads me to the music downloads, not to the complete Humble Bundle downloads.