Super Mario 64 is
one of the most important game of all time and it's well deserved, the enormous obstacles it had to overcome were the most frightening in the short history of the medium as a whole :
The jump from 2D to 3D, it was the far west, the technology was capable enough but the tools were lacking, the experienced programmers in 3D a rarity and every studios struggled during the transition, the temptation of going the easy route by transposing 2D gameplay into a 3D world, building a controller that allow 360° freedom of motions and camera controls.
Succeeding to Super Mario bros 1, (3) and world, each were crowning achievements at their time, 1 and world were launch titles too and system sellers, these games re invented platforming games and video games.
The cartridge format was a huge problem, not only cartridge data space was expensive and thus resulted in early games being 4MB to 8MB, the textures, sound were vastly impacted due to the lack of space available, considering SEGA and SONY had the CD format with 700MB available for their games NINTENDO were loosing the battle of 3rd party devs (SQUARESOFT) and their motives for keeping this old format was viewed as a desperate attempt to keep their high royalties fees and control.
SPOILER: SEE THIS REDDITOR ANECDOTE
The NINTENDO 64 took way too long, from it's "ULTRA 64" teasing in arcades with far better specs, the prospect of a SILICON GRAPHICS workstation power in a home console for just 249$ (then 199$ !) , the various delays, the hype from the various magazines, speculations... the PLAYSTATION and SATURN were months old at that point, with incredible leaps from their early titles to what they got in 1996, VIRTUA FIGHTER 2, PANZER DRAGOON ZWEI, WIPEOUT 2097(XL) RESIDENT EVIL !
SUPER MARIO 64
took 3 years to develop, an absurd amount of time for 1996, it was unheard of, the N64 controller was conceived around it (the analogue stick and C-buttons.)
The entire NINTENDO 64 plan was : SUPER MARIO 64, the success and future of the company was put behind it, from early as Nintendo Space World '95 when they decided to delay the system to '96 to have the game ready at launch,
to the declaration of then Nintendo president Hiroshi Yamauchi that "it would be the best video game ever created", it had massive expectations, even more when considering the Virtual Boy fiasco and the aging Super Nintendo, the CD-add-on debacle with SONY and PHILIPS.
And then, the game released, I remember at that time seeing on news at TV kids playing it, the fascination for the controller and what Mario could do, then seeing it in action at a friend house, the hub world castle with the paintings, the stars to collect, the objectives, the different effects from metal Mario to the weird ripples effect of the entry to hazy maze cave, the brilliant game design for each "puzzles" it was a revolution and the template for every game since, hell TOMB RAIDER came a few week after, but it was too late history had been made and everyone had Mario 64 to thank for it.
If you want to capture this particular era in great details I highly suggest you to read EDGE magazines from
November '95 to July '96 or if you want to make it shorter just the preview and review of Mario 64 in
EDGE 34 and
EDGE 35, EDGE was THE magazine at the time, nothing like EDGE of today, and Super Mario 64 earned the first 10/10 from the magazine, truly a time capsule and thankfully we had plenty of scans of it archived in the website I linked from 1993 to 2002 every issue is available.