Iwata was named president of Nintendo in 2002, leading its development of the hit Wii console and DS handheld, but before that, he was an accomplished game programmer.
The company said he died Saturday in a Kyoto University hospital after battling a bile duct tumour.
This quote of his from the Game Developers Conference in 2005 was widely shared on Twitter on Monday.
Iwata has been a favourite among Nintendo fans for his whimsical appearances in promotional videos at gaming conferences such as GDC and E3.
Although Iwata didn't appear in person at the most recent E3 because of his failing health, he was represented, along with other Nintendo executives, in Muppet form.
Among the most popular images shared about Iwata were screen shots of posts about his programming accomplishments before and after taking over as president.
Many gamers were moved to create fan art to mark Iwata's death, using some of Nintendo's most recognizable characters, such a Mario, Link, Kirby and characters from Pokémon.
This image was created by Tumblr user peachbunni.