The lead-up to SNES was an exciting time. My "golden years" were definitely growing up with the NES and then "graduating" to the Genesis. At the time, especially in that first couple of years, it felt absolutely incredible to have such a console at home playing games that looked like that. Mind you NES was still host to a lot of the best-playing games one could get their hands on and with the memory mapping chips they were still always improving by leaps and bounds (Batman: Return of the Joker looked like it was basically a 16-bit game, it was insane!) but Genesis really was providing a step closer to the arcade which didn't feel accessible otherwise (also TurboGrafx-16, but no one really cared about that console.. except me, sadly)..
Anyway when the mags finally started drip-feeding pics of launch window SNES games, it felt like a storm was coming. Basically, just like Genesis but EVEN BETTER. Pics of Mario World with the HUGE Bullet Bill, pics of F-Zero with the arcade-scaling track, pics of Ghouls n Ghosts with much sharper colors and details than we'd seen years earlier on Genesis.. and of course Nintendo was FINALLY getting an R-Type game, which seemed to be the missing crown jewel that the other systems had (to whatever degree) but was missing in the NES catalog. And of course Final Fight with those massive sprites!
Anyway SNES launch came and went and that first year or two was pretty legendary, with all the games already mentioned in this thread. In hindsight the Genesis did a pretty good job stacking up to it at the time - I am pretty sure they timed the release of the original Sonic the Hedgehog game right around that console launch, which did a really nice job of making Super Mario World (nice as it was) feel a bit stale on arrival. I grabbed (or rented) many of the other games I mentioned out of the gate, and they were all pretty stellar looking and sounded - Contra, Castlevania, Zelda 3, Star Wars, Mega Man X etc. But to be honest, though they were all great titles, I do feel like "the extra color palette, Mode 7 effect, crazy audio chip etc" were all very nice, but not enough to get me to pack up and forget my Genesis yet. And all those games, while they were really cool, they did feel like they were a bit rushed to get out for the launch and help show off he system (totally understandable) - but there was something about so many of those early titles that, in hindsight, didn't just allow them to wipe the slate clean with what their predecessors had done.
All these years later, I find myself replaying Mario or SMB3 rather than Super Mario World. Contra 1 or 2 (usually 1) on NES over Contra 3 on SNES. Castlevania 1 or 3 over the SNES version. Same with Ghouls n Ghosts (Genesis, not NES! Haha), even Zelda. Sure, none of those games "present" as well as their successors, but I think they were all a bit more dialed in, in some ways. Maybe it's just the nostalgia is greater for me, from when those games were new and exciting, versus when the upgrades came out and I was a little older and though they certainly looked and sounded "better," started feeling a bit stale, less special. But that is also sort of how I appreciate games as I get older anyway. I'll happily sit down with a simple game with very low-rent presentation nowadays so long as the mechanics, rhythm, etc is super-tight.