I'm of the opinion that there was really only one big generational leap (maybe two). That would be the leap from Gen 4 to Gen 5. Those new games simply weren't possible in any way on previous generations. The Super FX chip was pushed to its limit and couldn't handle something like Mario 64, even in a crude way.
And maybe the leap from Gen 2 to Gen 3. The ability to create whole levels and worlds rather than have single screens was a big jump for game play. But games like Pitfall could do that before, so it's not like it wasn't possible on earlier systems.
Any other leap is simply a graphical improvement. You get better looking environments, or better sound, or more/smarter enemies, or scripted events, etc. But nothing that was absolutely impossible on previous generations without some sacrifices. You get a few things here and there that refine gameplay like analog sticks, or motion controls, etc. But the games and what was possible to create, wasn't vastly different.







