Nice content Alec.
I think the UI could do with some refinement. Here's an example of a horizontal layout done right:
http://aspacecodyssey.com/#home
Things done right:
The user can use the mousewheel to scroll the page, as they would a vertical layout.
All the content is on a single page meaning that after initial loading, there's no waiting for shit to download.
The header navigation automatically scrolls to the relevant content so the user doesn't have to manually scroll.
The varying types of arrows utilised in the background compliment the layout and look rad while auto scrolling.
*edit
The general rule I follow for vertical layouts is to work within 960 pixels wide. You'll find most sites do this because everything fits within a browser at 1024 res and the width replicates what people are accustomed to looking at on paper. Wide or re-scalable (liquid) layouts generally look like shit (though there's always exceptions).
If you revise your current horizontal layout ensure each horizontal region fits within 960 pixels and most people won't need to scroll to see it.
I viewed your site on a system at 1900x1080. I still had to manually scroll to see all the content. It feels like a lot of effort compared to using the mouse wheel.