The leap from zelda snes to zelda ocarina of time. Ocarina of time is a revolution on gaming, it amazes me that nintendo delivered visuals and gameplay whit such quality in 1998.

GTA II to GTA III

-The original Street Fighter to Street Fighter II. It's something people don't necessarily remember, but the original Street Fighter isn't actually a very good game at all. It's clunky, kinda ugly, and by today's standards is honestly quite awful, whereas SFII still holds up quite well even today, as it improved upon its predecessor in pretty much every possible way.
-I don't really like to talk about visual improvements after from one console generation to another, because that's just obvious and unfair to the previous game. For example, saying that Metroid Prime was a huge visual improvement on Super Metroid or that FFX was an improvement compared to IX is just pointless because of course it was. Within the same generation however, Final Fantasy VII to VIII was a huge improvement in graphical quality, and then again from VIII to IX in even less time. Which game is bettthe best er can be argued endlessly, but visually Square made some massive improvements in little over three years.
-MGS2 to MGS3 is another big improvement in both gameplay and visuals in my opinion.

True I wouldn't say it revolutionised gaming but I felt it was a re imagining of open world gaming. Tbf I thought it was the weakest game on that list but the leap from Skyward sword is monumental :D

Sims 3 > Sims 4 (Better artstyle and runs better in not so powerful PC)

I'm going to go with Super Mario Bros over Mario Bros. Everything about the game was revamped, especially the controls. Rather than being restricted to one screen, the player could go for minutes in one direction. In addition, there were branching paths with warp zones leading not only forward, but also backward. Super Mario Bros introduced a variety of new characters and powerups as well as some of the best music in the business.

The jump from Metroid to Super Metroid also deserves a mention. No doubt, Super Metroid to Metroid Prime is also a gigantic leap, but for some reason it doesn't feel like the comparisson should be allowed. Metroid Prime may be a Metroid game, but I really don't feel like it is a continuation of the mise en scene of Super Metroid. I'm still hoping for that game one day, actually.

You could say that, but it is just the in-gen most impressive jump in a franchise for me.

I made it couple of months ago. People have put several good games like Mario on NES

Excluding some ridiculous franchise revivals, I'd have to say Metal Gear Solid 2. The improvement was especially noticeable in graphics and gameplay, and I think the graphics hold up even to this day. Gameplay-wise, first-person aiming made a huge difference, and so did the tranquilizer gun (and knocking out enemies in general). There was much more too.

Super Mario 64 was the biggest overal leap, in terms of graphics and gameplay.

Dragon Quest VIII gets my vote as the biggest graphical leap compared to its predecessors.