What are some of your favorites? A few months ago I pre-ordered a Retroid 5, and while my old 3 is no slouch, this one is better equipped to smoothly run more demanding titles like Smash 3DS or Dragons Crown.
Never had either system, so pretty much totally new to them. Just please don't list any Pokémon games, they're not my thing. Action games/metroidvanias are my preference, but I've also been on a huge racing game kick lately.
Kid Icarus uprising was a fantastic launch title but it's best played on original hardware due to gyro and touch controls
Starfox 64 3D is arguably the best way to play SF64
Metroid Samus returns is pretty good, although it's a bit polarizing because you have to stop moving to 360 aim and has strong emphasis on waiting for enemies to attack and doing a counter
Kirby superstar ultra has a mini metroidvania in it
VVVVVV has a 3ds port, but it's also natively on Android if the retroid is android-based.
Steamworld Dig 2
Cave Story or Cave Story 3D, depends on your preference of visual style.
Shantae: Pirate's Curse
Honorary mentions to Ocarina of Time 3D and Majora's Mask 3D
DS games:
The three Castlevania games on NDS are great.
Mario Kart DS is my favorite in the series. There's a lot to do in single player with all the developer time trial ghosts and a hefty missions mode.
Majora's Mask 3D is different, not strictly worse. And graphically it's better than N64. I wouldn't have a preference if I hadn't played Majora's mask on n64 as a kid.
Metroid Samus returns is pretty good, although it's a bit polarizing because you have to stop moving to 360 aim and has strong emphasis on waiting for enemies to attack and doing a counter
It's me I'm polarized. AM2R is better.
Also I'm upset that Dread took everything I didn't like about Samus Returns and doubled down on it.
Fire Emblem Awakening - Literally saved the franchise. One of the best installments to date in the series as well. Highly recommend playing it
Metroid Samus Returns - A good Metroid game that came late into the 3DS so not a lot remember it exists. It’s a remake of Metroid 2 and does it well.
Bravely Default - One of the best JRPGs I’ve played and I’ve played a lot. Robust job system. Great story. Love the Brave and Default mechanics built into the turn-based system. Super super highly recommended.
DS games from here
Super Mario 64 DS - I really love this iteration of Super Mario 64 and really wish Nintendo would rerelease it or give it a facelift. 30 extra stars. Four playable characters. Minimap on the bottom screen. Only, and I mean ONLY, downside is d-pad movement.
Avalon Code - Weird ARPG with a strange game system where you can modify most living things in the game. It’s odd but fun. Controls weirdly.
Luminous Arc - Fun SRPG series. It’s been well over a decade since I played 1 and 2, but I remember being very fond of them.
There’s more, but I’m blanking. Sorry if I didn’t super abide by your preferences, but I legit can’t think of too many Metroidvanias that aren’t explicitly Metroid or Castlevania.
Super Mario 64 DS - I really love this iteration of Super Mario 64 and really wish Nintendo would rerelease it or give it a facelift. 30 extra stars. Four playable characters. Minimap on the bottom screen. Only, and I mean ONLY, downside is d-pad movement.
I haven't tried it, but there is a mod out there that fixes this.
Oh yeah. I had completely forgotten about this. I’m going to have to hunt it down and load it up onto my 3DS. Thanks for reminding me of its existence.
Man both of those systems are so lame compared to their predecessors. PSP/DS is like peak handheld gaming to me, both have such incredibly varied and deep libraries
Any of the Guild series on the 3DS - they're all cool little games by a murderers row of Japanese game directors. Attack of the Friday Monsters! is probably my favorite
Digimon World Re:Digitize: Decode but you need to get a translation patch, the Vita version is the original but the 3ds port is the better version with much more content.
3DS: Azure Striker Gunvolt, Shovel Knight, Kid Icarus Uprising (idk if you have touchscreen controls but this game needs them), Mario & Luigi: Bowser's Inside Story (rpg, but I'm generally an action/metroid guy and I still love it)
DS: Mario Kart DS, Meteos (also needs a touchscreen, puzzle game but with a similar disclaimer as M&L)
I figured the Vita was mostly just for stealing games. You can put all sorts of things on that. There was a Soul Calibur game with Kratos in it. It sounded like a mess outside of Dampierre being an amusing guy.