There is only one NES game that I enjoy playing to this day. There is only one NES game that I consider to be just as entertaining now as it was in the 80s, without exception or extenuating circumstances. It was developed by Rare and is spelt Pro-Am. And it is incomparably good.
I know, I know. Super Mario Bros. 3 is the more popular choice, here. Not to mention the iconic first game that defined what the whole form of entertainment stood for, but for me it's the runner-up that rules this whole 8-bit series. There's so much charm in the old ultra-Japanese Doki Doki Panic that was remade into Super Mario & Co's second adventure, so much personality and fun design. I love the slightly rigid controls, I love the ability to pick up enemies (and objects), and the music.
Although Mega Man (the original game) was good for its time and still amuses, it's clearly the sequel that stands out. Because Mega Man 2 is a platforming masterpiece, so difficult and unapologetically iconic that you'll be tearing your hair out on the very first level. Capcom found the perfect recipe for the mix between difficulty and reward, the design is outstanding, and the music almost obscenely good.
In the 80s/90s, Disney ruled the world of licensed games with titles such as Quack Shot, Duck Tales, Aladdin, The Lion King, Castle of Illusion, and many more. Best of all was Capcom's furiously charming, challenging and varied platform adventure starring Scrooge McDuck. It really was quite brilliant and contains what is probably the best game music ever made.
A slightly odd winner? Well, maybe. Perhaps the most expected thing would have been to put Super Mario Bros. 3 in here (the Mario game I like least for the NES, actually) or why not the super classic The Legend of Zelda (which is and was great, but not top five in my book). Instead, it's Nintendo's immortal boxing project that rules my top list and a lot of that is down to the fact that the game is still just as fun, challenging and mechanically perfect today as it was 40 years ago.