Devs who've worked in the industry for years, even decades, are apparently blown away by just how the heck Nintendo managed to make Tears of the Kingdom. Here are a few articles and tweets covering their reactions; you can find many more, these are just the ones I stumbled upon since release.

Really goes to show what an impressive achievement in design the game is, that folks who do this stuff for a living struggling to fathom how it's even possible.

https://www.forbes.com/sites/paultassi/2023/05/18/no-one-understands-how-nintendo-made-the-legend-of-zelda-tears-of-the-kingdom/?sh=2aed1d92bfb1

"No one understands how Nintendo made The Legend of Zelda: Tears of the Kingdom."

https://www.bloomberg.com/news/newsletters/2023-05-26/-the-legend-of-zelda-tears-of-the-kingdom-dazzles-game-developers

“The level of attention of detail and care put into all of these different interactions, given the sheer scale of how many interactions you can have. It’s just a degree of diligence and artistry that you don’t see very often.”

“Honestly jaw-dropping. It’s such a smooth experience I imagine most people won’t notice or think about how incredibly difficult it is to pull it off.”

https://www.gamesradar.com/game-dev-blown-away-by-zelda-tears-of-the-kingdom-says-it-shouldnt-be-possible-on-the-switch/

"Each one of these systems would have been astounding if it was just it by itself. To have it all happening at the same time and all of it to be interconnecting and working and playing nice with each other while the entire Legend of Zelda game, the normal loop that we experience from Breath of the Wild, is just laying right on top, that doesn't seem possible."

"They're doing things that people thought were impossible on modern hardware. It would be a monumental thing to do on current next-gen consoles."

Here's a game dev (@ModestLaw) explaining why Tears of the Kingdom is such a technical achievement. pic.twitter.com/q8arTEBfZf

— Andy Cortez (didn't pay) (@TheAndyCortez) May 21, 2023

Hey Nintendo, quick question regarding Tears of the Kingdom:

how in the fuck did you make this

— Josh Scherr, allegedly (@joshscherr) May 15, 2023

The game programming flex of all time. pic.twitter.com/id2K5uE5mz

— William Armstrong (@WillWArmstrong) May 21, 2023

I'm still shocked by the Fuse mechanic. The way they automatically calculate how to best position the items by themselves is wild. Also the way the physics interact with each other. Sometimes in BOTW I felt like the gravity and other forces were a bit erratic, here I feel they are just perfect

The way they added ultrahand to allow you interact with much more objects than just metal (and changed the clunky motion control use of it to a very proper alagotic control) is game changer

As far as core gameplay mechanics are concerned this game is 2 to 3 levels above BOTW, therefore at least 5 levels above anything else in the industry lol

I can see why it took so long to be developed. The work to make physics work without compromising any aspect of the game was probably a hell to code

 I saw someone build a full-sized and functioning Yaht. Someone built a mech that worked. A Macross Jet. A full-functioning Metal Gear Rex. Lewd wood men ejaculating because of course. The fuse system is mindblowing.  Now we get to watch other devs poorly try and copy it like that mediocre BOTW clone from Ubisoft. Boy, that game was dull.

The funniest thing was watching a literal rocket scientist be blown away by the physics of a chain and wheel opening a door that is not canned animation. The chain has collision and physics allowing it to be possible. PS4 TLOUII had one segment of that game with a rope that blew people away. Yakuza 7 with bread blew people away. The judgment stairs animation blew the devs away. Yet on this 8-year-old mobile chip, Nintendo has bested all of them.

Hey don't leave death stranding out. That rope mechanic from tlou2 is still epic to this day. I only just reach the storm in the cloud part , but physics wise I haven't been that blown away, yet. But the game is gorgeous. When u shoot up to the clouds , on my lg c2, game looks amazing. Was in awe

Now I want to see Ellie build a mech and rampage through Seattle.

This is why I find it hilarious when people on forums try to dismiss this game and pretend like it's not impressive or an achievement.

Courtesy of the Lunchpack engine. I thought BotW and TotK had their own separate engine, but apparently they're running in the same, albeit modified, engine as all the Splatoon games, Switch Sports and Nintendo Land.

I'm not qualified comment on the technical aspects of this stuff. But, I can say from a gamer's perspective that the ascend, fuse, and ultra hand mechanics are fun to play with, and they make the game feel unique. In fact, I think they really are one of the reasons that you don't hear many complaints about reuse of the BotW world. They have significantly changed the way that the gameplay works. When combined with the addition of the sky and the underworld, at some points, I barely even notice that I'm playing a game set in the exact same place as the last one.

Nintendo's limitations in their hardware have led to some impressive achievements, considering. And it's not limited to first-party games. Resident Evil 2 was crammed onto an N64 Game Pak with a lot of compression and more effective use of storage space. The Witcher 3 with DLC was crammed onto a single 32 GB Switch Game Card.
Most Nintendo games on Switch tend to be under 10 GB. I think devs have gotten too complacent with not utilizing space better. I understand the textures and AI are usually more advanced, but still.
I don't think any Nintendo game in history has been higher than the 25 GB or so range with all updates and DLC (Xenoblade Chronicles X). The Wii U is a little stronger than the 360 and PS3, but with a worse CPU. And the Switch is better than the Wii U or PS3 and 360.
Uncharted 3 was abou5 43.5 GB on PS3 way back in November 2011. That's so wild, and most of that space was probably the cutscenes and not using the space more effectively.

This is the biggest reason I find fault with your very popular thread that you created on the day the game released.  I'm not going to call your thread bait, but I do think you are guilty of the adage: "when all you have is a hammer, everything looks like a nail."  You are primed and ready for a Switch 2.  You're jumping at the opportunity to get on with the next revolution or next iteration, and I understand that.

But you chose the wrong nail to hammer.  TotK, mostly for the reasons you just mentioned, but also for the reasons outlined by the comments by developers in this thread, is a technical marvel and a joy to play that actually argues against your thesis.  If all games could come out with the polish, scope, and joy of this title we wouldn't have a need for any future Nintendo console.  Of course, that isn't the case and it certainly isn't what I'd argue for.  I just really think you chose the wrong vehicle for your argument.

So glad to see you come over to this thread and set the record straight for all of us.