Kid icarus can easily be the best 3DS game
it stands out so much, the action, the great visuals, the excellent use of 3D (i never use it except this game) how it wasn't a console game i'll never know. remake it nintendo please!?
I really really like Bravely Second, it's not only to me the BEST FINAL FANTASY GAME (its basically FF gameplay like FF5 more so) but so far my favorite JRPG ever. i wish second gets a remaster
btw, NOT DEFAULT 2, BRAVELY SECOND, they are not the same game, thank square enix for that.
I really like fire emblem awakening, more than fates, idk why, maybe the multiplayer stuff was good, maybe i wasn't a fan of the 2 seperate games plus DLC side ( i did all 3 routes of Fates, i think it should've just been Revelations and thats it) or just the story was better to me on Awakening.
have not played shadows of valentina so we'll see how that goes.
Dragon quest 7 and 8 are very good on 3DS, idc what anyone says, they were NOT better on PS1/Ps2
DQ7 on PS1 was SUPER SUPER SLOW, it's the longest DQ game in the series, you spent almost 2 HOURS not fighting a single monster at the intro!! the 3DS DQ7 streamlined this to a couple of MINUTES, still very long on 3DS (over 100 hours i never spent that much time on a DQ game)
DQ8 yeah the ps2 version is obsolete, 3DS verison has MORE content, sidequests, postgame, PLAYABLE CHARACTERS, new story scenes. camera missions, new skill trees. it's also faster than ps2, no load times, faster combat speed (as an option) i forget what else there's too much better
both games on emulation look amazing if the low graphics bug you, and a music patch for 8,
the 3DS donkey kong country returns is cool, if you don't have access to the switch remake, it's not terribly diferent other than resolution. had a blast on the SNES donkey kong country games and this is right up there. harder to multiplayer on 3DS obviously.
the Zelda ocarina of time and Majoras mask 3DS versions are much improved over their originals,
i actually hated majoras mask on N64, the game put too much pressure of time and it made it un-fun most of the time... i used cheats to stop the timer on N64 version and had way more fun
the 3DS majoras mask is so much more easier to manage, slower timer, a quest book, with reminders for time sensitive quests popping up, and way more save points! and some things don't repeat on each time loop.
Theatrhythm Final Fantasy curtain call, its so much fun if you love rhythm games
yes theres a newer game out there (final bar line) but they're both different enough. and playing on the touch screen is an experience. i like the quest mode on 3DS over the newer one
Puzzle and dragons Z + super mario bros
if you really like puzzle games, match 3 games (it's much more you can move pieces anywhere not just one square nearby) with a mix of RPG in there, this is fun, and feels better on a 3DS screen (sliding pieces around by stylus) but works well on emulation and mouse too. its two different games, the mario side is obvious, and the Z side is it's own original story. Z side is more complex.
i was a huge fan of puzzle quest so i liked this one just as well.
sonic generations, the 3DS has different levels, i like this and the console version generations, top sonic games, before it all got progressively worse.
(sonic x shadow generations is so much fun on a side note)
the 3ds sonic colors is almost entirely different, i like the 3ds one more actually
River City Rival showdown, played well on 3DS, the newer PC/console port has it's changes (like local co-op) check it out, if you've never played any river city/Kunio kun game, this is the First River City NES game remade. there's also tokyo rumble a much shorter game, and river city three kingdoms, extremely dialog heavy but basically playing out dynasty warrior like plot
i'll stop here, i have a huge backlog of 3DS games which is most of what everyone else said here.
other mentions: project x zone, 1 and 2, massive crossover SRPG with capcom, namco, nintendo, etc.
code of princess (has newer port) beat em up, very similar to guardian heroes.