I can make it possible!
@labris after looking at the website it looks like you could accomplish this with the down scroll still and just animating your scene to the left or right. Not really sure how they did theirs but its nice, I don’t like how you cant see the scrollbar though! I am trying to get the 3d website up and running here soon that uses it and maybe that will make more sense than on how to do it with scrolls. You would basically just do a fixed div over a body of a set height to accomplish this effect with scrolls.
If you really need the horizontal tracking though for some purpose I can add that.
@labris is this what you were talking about:
https://pryme8.github.io/scrolls.js/examples/bjs-example-2.html
Or are you looking for specifically horizontal scroll support?