1.
Sonic 3 & Knuckles
Everything about the original, but better. Catchier (Michael Jackson!) music, richer graphics, better-developed gameplay with more power-ups and "cinematics" and interactive elements. Plus the whole lock-on concept just felt stupidly cool, especially when you threw a Game Genie into the mix.
2.
Sonic the Hedgehog
The second video game I ever played, and it still holds up today (I just beat it again recently on iOS). Ridiculously fluid, vibrant, and melodious, with diverse environments, brilliant bonus stages, and a killer core concept that people still clamor for almost a quarter-century later.
3.
McDonald's Treasure Land Adventure
It looks so silly at first glance, but Treasure's adver-game proved one of the most ambitious titles on the system. Defined by bizarre enemies and manic, fever-dream level design, featuring everything from haunted world-trees to shadowy conga-lines of ballerina bunnies.
4.
Castle of Illusion
Expansively imaginative, this game always felt like an epic journey even if it could be beaten in a half hour or so. Such a wide range of worlds to explore, with an evocative score, creative boss battles, and charming sound design.
5.
Aladdin
An excellent conversion of the film, retaining the wit and visual gags with a challenging platform design spanning long and complex levels, plus a nice assortment of bonus games to mix things up.
6.
The Lion King
Not quite as faithful to the film's tone, but makes up for it with great music, colorful environments, and a cool African-inspired interface.
7.
Ristar
A nifty platformer with some unique gameplay mechanics.
8.
Mighty Morphin Power Rangers: The Movie
My first fighting game was the original 2 v. 2 Power Rangers title, but this sequel expanded its scope markedly with a full-fledged campaign across multiple large environments and an assortment of bosses.
9.
Ghouls 'n Ghosts
I'll admit, I never got past the first level, but that's what makes this such an infamous title, right?
10.
Altered Beast
My first ever video game. Lacks the charm of some of these other title (especially Sonic, which was a well-deserved replacement launch title), but you'll never forget your first.
Dishonorable mention: Fantasia. That shit was just awful.