The gold crowns have been officially implemented and described. Advanced rulings can be found in the Gold Crowns page; one ruling is that gold crowns are mobile/HTML5 exclusive, and failures do not count if you fail in the web version.
In the last day or two a bunch of my level icons have turned gold with little crowns on top. Some I have 3 stars, some only 1. They're also not levels where I have the high score, because then all of levels after 2593 would be gold since I'm the only one of my friends whose gotten that far. It only starts with the Wafer Waterfall episode (level 2586). Anyone know what this is? My only is guess is maybe levels that I completed on the first try, but then why does it only apply to the last 3 episodes?
This also happened to me. I am currently on Choco Rio Grande. The gold levels affected those on my current world. It have to do with the newly introduced XP system, which currently only grants extra lives and sometimes make your border fancier.
Oh, interesting. I hadn't seen any affect at all from the XP or when I leveled up.. I was expecting boosters or something (maybe I got my lives refilled and didn't notice). But what do the gold levels *mean*??
And now the next mystery... I loaded the game this afternoon and all the gold icons are gone! I'm so confused.