From what I understand, most of Super Nintendo World's land effects break down consistently and require a lot of maintenence. There is only so much manpower they can give the land, so instead of fixing everything at once they essentially only have half of the land effects going at one time, and work on the others until the operational ones go down again.
The main Key Challenge Thwomp effect has only run for maybe a month's worth of time since previews. It's supposed to have mist effects to emulate the dust particles from the game, but those almost never work, even when the big guy actually is dropping. I've been lucky enough to see the full effect and it's very cool, a shame it's apparently such an issue.
Spiny apparently went down for over a month, but he's back now. He might have some of the most moving joints of all the SNW characters, weirdly enough. He looks great honestly haha.
There's a hard to spot Koopa Troopa above the Jr Showdown building. He's meant to be walking back-and-forth behind the fortress walls, but I've never seen him work once. From what I understand, he may move if Nintendo is in the park, but sometimes even that isn't enough. They can barely keep the Koopa above the Key Challenge working, so :shrug: . Seeing Showdown Koopa operational is definitely a longterm wish for myself.