It was very similar to this site where you had jarring transitions, background changes and images moving at different speeds. https://doubble.group/sg/
The end result was very similar to site above and we all got a lot of positive feedback when their current clients saw it because they were blown away. While I was busy separating my shoulder patting myself on the back - we realized a few months in, the engagement was horrendous. The leads from their contact form dried up to almost nothing. Analytics showed an insane drop off from the home page. None of the internal pages were getting any traffic. We quickly realized that nobody could find any content on the site, they couldn't get to the contact page very easily, the content was hard to find and or read because of the motion and animation that constantly took your focus off of what you, as a user, were trying to do.
We had up for four months before having to pull it and put up their old site, then re-design another simple, more refined site that would work better for their users. It was a great lesson to learn about solving problems or trying to create something cool that nobody could use.
We also designed a site for a local event to support a women's shelter and used parallax again to tell a story of how women are shuffled through a system that does little to protect them from their ex-husbands or violent abusers.
It used the same techniques in this, where you had both horizontal and vertical scrolling in both directions to show a timeline and story with illustrations and infographics. https://collagestudio.ca/en
This also got a ton of good feedback and we had a few other non-profits approach us to do something similar for them and we did a few more using the same template we had, but switching some elements to make it original for each client. This worked out much better because if people were able to digest the story and the points you were trying to make, it had a better impact than new clients trying to find specific content and the contact page.
Hope that helps!