RetroGaming

SNES

• the Donkey Kong Country trilogy, just good platformers; first one hasn't aged as well as people think, if you don't enjoy it skip ahead to 2 and come back later if you feel like it
• The Lost Vikings 1 and 2, fantastic character-switching co-operative (but playable solo) level-based puzzle-platformer; don't play the sequel on newer platforms like PlayStation, they tried to modernize the graphics and only succeeded in making them hideous, stick with SNES
• Star Fox 2, as long as you enjoy dated 3D and poor framerates, this is the most ambitious 3D game on any 16-bit console, with a very replayable campaign full of hidden unlockables that differs on each play
• Super Mario All-Stars & Super Mario World, just an enhanced compilation of 4-5 seminal 2D platformers; while you could use save states on the NES versions, the SNES versions all support native saves, so easier to pick up and play
• Tetris Attack, nothing to do with Tetris, just a match-three puzzler with deep, engrossing mechanics that can keep you interested long-term; also Panel de Pon with a translation hack if you want more
• Top Gear, fantastic competitive racer with the line-scroll road effect you know from classic arcade games like OutRun and a killer soundtrack; pick the white car
• Yoshi's Island, another classic platformer

Mega Drive/Genesis

• Gauntlet IV, better than the arcade original, this is M2 (now known for developing emulators for many classic systems) flexing with some RPG mechanics added to the traditional Gauntlet gameplay
• The Lost Vikings, SNES version is better but there's a few brand new levels in this one if you want more
• Sonic the Hedgehog 3 & Knuckles, basically the first Sonic that noticed it's a home game, so it has saving and improved replayability with multiple characters, paths and unlockables

Game Boy

• Donkey Kong, this is not a port of arcade Donkey Kong, it's a full-blown puzzle platformer you can play one level at a time
• Kirby's Dream Land 2, easy-to-finish platformer but with tons of content if you're playing "properly", using the sort of rock-paper-scissors logic to use the right powers to enter the secret areas
• Super Mario Land 2: 6 Golden Coins, just a proper "mid-period" (SNES-esque) Mario platformer which you can play over as long as you like

Game Boy Color

• Balloon Fight GB, predates Flappy Bird by literal decades but like if that was a proper game with a campaign
• The Mummy, based on the Brendan Fraser movie and an awesome Konami puzzle-platformer with short individual levels and password save (use save states on emulator), super underrated
• Pokémon Puzzle Challenge, Tetris Attack but with Pokémon if you prefer that theming
• Wendy: Every Witch Way, based on some kind of comic book I think, developed by WayForward who developed the Shantae games and then branched off into Yacht Club Games (Shovel Knight), Wendy is a gravity-flipping platformer where you're in control of which direction is up or down

Game Boy Advance

• Advance Wars 1 & 2, adorable turn-based strategy war game with a campaign based around small, self-contained levels, except for a few huge ones
• Drill Dozer, developed by Game Freak (Pokémon), is a sort of level-based Metroidvania platformer with lots of backtracking to older levels as you unlock new abilities
• F-Zero: Maximum Velocity, the only true sequel to SNES F-Zero, don't at me
• Game Boy Advance Video: Shrek, endlessly replayable
• Metroid: Fusion and Zero Mission, they're Metroid games
• Super Mario Advance 4: Super Mario Bros. 3 e-Reader version, I think you can get this officially on Switch somehow, but you've been to the Internet before; this officially-released modified version of the original game includes a bunch of brand new levels previously distributed only on scannable cards, I'm not telling the whole story but they remix elements from the first four mainline Mario games into basically a whole original game. This is New Super Mario Bros. this is Super Mario Bros. 5, still don't at me