Back on topic. I think alot of retro games hold up excellently today. Yeah, there's some broken games, but I still feel that the Mario's, Zelda's, Metroids, Contra, etc. hold up excellent compared to today. I think early 3D looks terrible so the N64 is hard to play in general. But if I can get past the headaches those games give me, they are fundamentally sound.
Better/worse than today? The only thing gauranteed to be better is the graphics. Physics usually are tweaked, level design is changed, and powerups are changed, but fundamentally NSMB might as well be Super Mario Bros 4, 5, 6. The only big changes are when 2D games become 3D games and lots of times they lose their identity and become worse games. Sometimes they are great games such as Mario 64, but that really makes it hard to compare to the 2D Mario's.
My love of Nintendo started when I didn't get an NES. I was obsessed with pulling all-nighters with friends or playing it at family members houses. Mario and Mega Man were awesome but really Techmo Super Bowl was the game I'd play the most. Since I didn't have a system, my friends and I would try to do one season in one night. Sometimes we'd make it, sometimes not.
Then my parents got me a SNES with the Mario All-Stars, Mario World, and Zelda. I beat them all and loved every minute. I got to play with my sister alot too which was great. I never really owned alot of games, but there had to be several games that I rented out (when that was a thing) multiple times and the library was just outstanding. Playstation became popular when I was in college. While the "mature" marketing certainly worked for them I was always kind of turned off by it. I didn't think I needed to play a mature game to feel like a man, and FPS are my least favorite genre so that was never a reason to leave Nintendo. Then I bought my first console (a Gamecube) and I just loved it cementing a place for Nintendo in my heart.
Props to Adrock. "I feel the exact opposite way you do. GameCube, to me, is Nintendo's strongest console after SNES (N64 is close behind). It has three of the best games I've ever played (Melee, Prime, and RE4)."
Gamecube just doesn't get enough love. I missed the N64 first time around so getting Double Dash, Zelda Collector's Disc, Rogue Squadron, Mario Tennis/Golf were awesome for me too. Plus, the first time I played Remake I knew I had to get the rest of the survival horror series because that was brilliant. Throw in Wind Waker, Pikmin, Monkey Ball, Eternal Darkness, and it had a great library. I have 80+ games for it, I could go longer but I'll move on.