This is 3DS ROM #2070

Japanese title: Zelda Musou Hyrule All-stars
Translated Jap title: Zelda Unmatched Hyrule All-stars
English title: Hyrule Warriors Legends

Released for the 3DS in Japan on 2016-01-21.

This is the japanese version of the game..

It seems that the company "Koei Tecmo" actually published this game and not Nintendo.. It is because this isn't really a normal Zelda game.. It is really just part of Koei's series of games called "Musou", but it seems they collaborated with Nintendo some how to be able to make a Zelda version of Musou.. That is why you will notice that this does not play like a normal Zelda game at all.. Instead it seems like a button-mashing game where you just slash tons of enemies through-out the entire game..

The game "Zelda Musou" was actually already released for the Wii-U in Japan on 2014-08-14..
This 3DS version of it is the same but has some differences:
>The 3DS version includes all previously-released DLC (Downloadable Content) that was released for the Wii-U version.
>Features the ability to switch characters instantly.
>It adds two new story chapters: one based around new character Linkle, and one featuring characters and environments from "Zelda No Densetsu: Kaze No Takuto"(The Legend of Zelda: The Wind Waker) that serves as an epilogue.
>There are also at least two new items confirmed to be appearing, those being a golden Ocarina and a Hammer.. The Ocarina allows Warriors to warp to different Owl Statues.. The Hammer functions as a heavy weapon, which can be used to weaken the Helmaroc King and to activate Warships..
>The game also introduces the Smash Boost Power effect.. By gathering up to four playable Warriors against a boss, the effect can be activated.. By doing so, the Magic Gauge is restored..
>Link's Spinner weapon is available from the start instead of being unlocked via the Link or Toon Link amiibo..
>"Challenge Mode" has apparently been removed from the 3DS version for some reason..
>A new game mode, called "My Fairy", allows players to befriend Fairies and use them in battles in Adventure Mode.. These Fairies can be raised in a number of ways to grow stronger, and can learn new skills and attributes that increases their proficiency in battle.. The mode also lets players customize their Fairies' appearance in costumes called "Fairy Wear"..
>It adds some new characters:
>>Tetra
>>Hyrule Ou (King of Hyrule)
>>Sutaru Kid (Skull Kid)
>>Toon Link
>>Linkle

It is also possible to transfer these new characters over to the Wii-U version using a download code which is included with the game.. However, I don't have that code and have no idea how to get it..

Concerning game-play: You can only use 3D-mode with the New-3DS.. The Old-3DS can only play it in 2D-mode.. This is because the Old-3DS's weaker hardware can not handle rendering this graphics-heavy game in 3D-mode with out exploding in to a million pieces.. To prevent users from potentially being harmed by an exploding 3DS, Nintendo has disabled 3D-mode for the Old-3DS for the purpose of safety..
However, it seems that the title-screen and movies are still in 2D even on a New-3DS, but the game-play will be in 3D..

This is a single .3ds file inside of a .7z archive file..

You will need a gateway card (or some kind of CFW) to run it on your 3DS..
Also, make sure your gateway software is updated to the newest version..
At the time of this writing you need to have your sysnand on 9.2.0 or lower.. However if you have 10.3 or lower, there is a way that you can downgrade your sysnand to 9.2.0. (You will need to research it on a site like gbatemp.net to figure out how to do it).. But if you are on sysnand 10.4 or higher, it is not possible (at the time of this writing) to downgrade or hack your 3DS..
This game is 4.0 GB (when extracted), so you will probably have to split it using the gateway ROM splitter before you put it on your micro-SD card for the gateway card.. Only fat32 is officially supported by gateway (exfat causes problems), and of course fat32 doesn't support files bigger than 4GB (I think this game is just slightly over the limit)..

I have confirmed it to work at least with this set up:
new-3DS
sysnand: 9.2.0
emunand: 10.4.0
gateway launcher software version: 3.7.1