Okay... Are you deliberately scrolling both horizontal and vertical? I can't tell exactly what is in motion and what should be standing alone.
It seems that the overlay is larger than the screen size, I don't use the sticky much so I'm not very helpful, I'm sorry. But I think you be able to box the column width and perhaps pad the outside border so that it all stays contained within the screen.
I like the way the titles look, but the image seem to be off screen. Make sure you don't have negative margins.
I like the way the cakes come together - that is a cool effect. I wish I could be more help. I would love to see your finished product.