I moved my scroll wheel a single tick and the content of the browser window completely changed with no movement to indicate scrolling was happening.

The change was so sudden and stark that I thought some sort of error had occurred and I was looking at a broken render of whatever I should be seeing.

Might be slightly better if the background didn't change color as soon as you move off the first "slide". Then it might not feel like you left the site or got dumped to an error page.