999: Nine Hours, Nine Persons, Nine Doors
Publisher: Spike, Aksys Games
Available: JP, NA (Also it has an iOS release)
This is one heck, amazing, terrifyingly beautiful of a "story". Enough said.
Black Sigil: Blade of the Exiled
Publisher: Graffiti Entertainment
Available: NA
This is one of the most underrated games ever. Truly a hidden gem.
Contact
Publisher: Marvelous Entertainment, Atlus, Rising Star Games
Available: JP, NA, PAL
Apparently a "weird" hidden gem. But a very loved one. Play it.
Digimon World DS
Publisher: Namco Bandai
Available: JP, NA
This is a pretty fun game. You can actually do more things than just training your Digimon.
Draglade
Publisher: Banpresto, Bandai Namco Games, Atlus, 505 Games
Available: JP, NA, EU
This is a good game that has a lot of potential. Not only this is a fighting game, but a musical game to boot.
Final Fantasy Fables: Chocobo Tales
Publisher: Square Enix
Available: JP, NA, AUS, EU
I could go on using synonyms on "light-hearted, fun, adorable, sweet" about this game, ya know.
Flower, Sun, and Rain
Publisher: Victor Interactive, Marvelous Entertainment, Xseed Games, Rising Star Games
Available: JP, NA, EU
If you can look past the graphics and gameplay, this is surprisingly an enjoyable game.
Enjoy, hahahahah...
Henry Hatsworth in the Puzzling Adventure
Publisher: EA Games
Available: NA, EU
A nice and splendid combination of platforming, action and puzzle. A decent addition to the DS collection. Highly rated by critics, by the way.
Okamiden
Publisher: Capcom
Available: JP, NA, EU, AUS
Pretty amazing and sweet game, if you ask me. Play the first one,
Okami.
Ontamarama
Publisher: Noise Factory, Atlus
Available: JP, NA
Can be addicting. Also cute.
Meteos
Publisher: Bandai, Nintendo
Available: JP, NA, EU, AUS
Interesting and quirky story and setting. This is a pretty good puzzle game, can be addicting.
Miami Law
Publisher: Hudson Soft, Konami
Available: NA, JP, EU
A game that has potential if improved in a lot of ways. You either shoot criminals or solve puzzles.
My World, My Way
Publisher: Global A Entertainment, Atlus
Available: JP, NA
Hilarious and quirky, this game is worth the play with its funny story, "commands" and likable characters.
Time Hollow
Publisher: Konami
Available: JP, NA, EU
One of the many games that has lot of potential, and whom I wished that has a sequel.
*Sniff*