I didn't notice the effect until I scrolled back up and saw a jerky movement in the buildings. Then tried scrolling back down and up not getting it to work until I noticed it moved with the mouse movement not the scrolling.
You've created a nice showpiece. However, it's still a horrible design trend, and it's probably the work user experience element I've seen used in recent years. This is the equivalent of the animated gifs of the 90's. Under construction and dancing baby being the most common. Adding distraction rather than focusing on content has never been a successful strategy, and I hope it never does.
It will course correct eventually. I'm hoping sooner.
[shameless plug] I've used (almost) the same effect for my landing page for my upcoming film:
http://salesmanfilm.com/
(P.S: Scrolling might be choppy on Retina MBPs/slower configs)