The heartfelt tributes are clearly the result of Iwata's quirky, disarming personality, and his abiding commitment to building memorable games.
During his 13-year stewardship of the Japanese gaming giant, Iwata introduced innovations that re-energized the company without betraying the fundamental philosophy of keeping videogames fun and accessible, says Julian Spillane, a Toronto-based developer who has worked with Nintendo and met Iwata on several occasions.
"He made Nintendo relevant again," says Spillane, thanks in large part to the release of the handheld DS system and the Wii motion-sensor console in the mid-2000s.
Those trailblazing products were all part of a "rigid focus on highly playable games for basically all ages, and that's something that Sony and Microsoft were completely willing to abandon," adds Neil Randall, director of the Games Institute at the University of Waterloo.
Iwata died on Saturday from a bile duct tumour. He was 55.
The Entertainment Software Association released a statement on Monday saying that his death "affects us all deeply. He was a true visionary who expanded our understanding of the amazing art of video games."
'A true visionary'
Iwata started out as a programmer at Tokyo-based HAL Laboratories, which often collaborated with Nintendo, and helped develop such popular titles as Balloon Fight and Earthbound.
He also worked on the creation of Kirby, a squishy character who would star in a raft of upbeat Nintendo games, including Kirby's Dream Land (1992) and, most recently, Kirby and the Rainbow Curse (2015).
Iwata joined Nintendo in 2000, and two years later became the first person from outside the founding Yamauchi family to be made company president.
He succeeded Hiroshi Yamauchi, who had been at the helm for 53 years.
Nintendo had built its reputation on indelible titles such as Donkey Kong, Super Mario Bros. and Legend of Zelda. But Iwata took over at a time when the company's consoles were going head-to-head with newer systems, such as Sony's PlayStation and Microsoft's Xbox, notes Stephen Totilo, editor-in-chief at gaming site Kotaku.
Nintendo was "facing a lot of competition and a general feeling that maybe they were a thing of the past, that they were a childish amusement not meant for a grown-up videogame scene," says Totilo.
Under Iwata, Nintendo's answer was to release the DS, a portable system with a clamshell design that featured two screens — one of them a touch screen.
The industry's initial response, says Totilo, was ridicule.
"The rival from Sony, the PSP, was sleeker, more powerful. The conventional wisdom was that Nintendo had no idea what it was doing," says Totilo.
"But the conventional wisdom, when it came to Satoru Iwata, was often wrong."
Consumers quickly took to this new device, thanks in large part to the sophisticated gameplay of titles such as Super Mario Bros. 64, educational puzzle game Brain Age and pet-raising simulator Nintendogs.
According to Nintendo, as of September 2014, the company had sold over 154 million units of all DS models combined.
Iwata also oversaw the release of the Wii, the company's motion-sensor console, a "colossal" product that signified the company's "giant comeback," says Jeff Ryan, author of Super Mario: How Nintendo Conquered America.
The Wii featured a wireless controller that used the player's body gestures to control action on the screen – from wielding a tennis racket to driving a car.
The Wii didn't look like a conventional videogame console, and its ease of use, as well as the variety of available games, had appeal beyond the traditional gaming demographic to include women and older consumers.
The result for Nintendo? Huge profits.
Ryan says that, upon release, most new consoles sell out for a month or two. The Wii went well beyond that.
"The Wii sold out for three years straight," says Ryan. "At any given time from 2006 to 2009, you couldn't find one in the store."
Moving to mobile gaming
While the DS and the Wii have been unmitigated successes for Nintendo, Iwata and the company have been criticized for only recently deciding to enter the mobile gaming market, which has seen huge growth in recent years thanks to the proliferation of smartphones.
This spring, Nintendo announced plans to market five games for smartphones and tablets by 2017.
Part of the reason that Nintendo held out so long is that the company has always made money on both their hardware and software, and "if you start giving your software to smartphone companies, or if you put it on Xbox or PlayStation, people have no reason to buy a Nintendo," says Ryan.
Randall at the Games Institute says another rationale for rejecting the mobile market is that "the vast majority of smartphones games are bad," and Iwata wanted to "assure Nintendo buyers that they were going to maintain the quality of games."
'I am a gamer'
Many of the obits and social media tributes that have been written in the wake of Iwata's death have cited a 10-year-old quote that crystallizes his philosophy and outlook.
Standing on stage at the 2005 Game Developers Conference in San Jose, Calif., Iwata said, "On my business card, I am a corporate president. In my mind, I am a game developer. In my heart, I am a gamer."
According to Spillane, there was no better illustration of Iwata's enduring interest in the act of creating exciting, immersive videogames than the "Iwata Asks" series of videos, in which the Nintendo president sat down and informally interviewed Nintendo employees from game developers to translators.
"Traditionally, Nintendo was a very closely guarded company. They did not share secrets," says Spillane.
Spillane says the "Iwata Asks" videos used the president's innate enthusiasm to bring Nintendo's fans closer to the inspiration behind the company's most beloved titles.
The series "created more legends about [Nintendo's] products and processes and it really just added to the mythos of the company," says Spillane.