Kong Falls originated with Melee, but I never noticed it wasn't ever in Brawl or Ultimate. Like all retro stages, it's mostly the same, but with some graphical tweaks to make everything look nice and good in HD. It was based on a tiny section of Donkey Kong Country.
Like most early stages, there's not any hazards. The only thing to be careful of is this narrow rock pillar. It can make for an easy fall if you're not careful.
But overall, while not my favorite stage in Melee or the series in general, I was glad to see it return.