It's something new IMO but we are definitely working on improving UX still. Fixing the overscroll issue as we speak. I'm assuming you're using mobile, would you prefer it of the 'tiles' all started in an open state?
It is not an experiment in how bad front end design can be pushed to be... Although that would be a fun blog post
I am not on mobile. It all boils down to the way decade old convetions/expectations are broken.
The things that look like buttons (and are spans in the html code, not even anchors!) trigger non-local transitions (the left panel thing) when hovered... and they close the opened panel when clicked, so if I move my mouse to click on it the end result is a panel that flashes.
I need to keep ignoring the usual button affordance of being clicked and force myself to think they are tiggered on hover.
If this isn't bad UX I don't kown what it is.
I think the site looks fine. Just remove whatever is changing the scrolling and adding "smoothness" to it or whatever. Showing stuff as you scroll is cool, but interfering with the scrolling itself is not cool.