Nintendo released a new title in Japan called Tank Trooper which was announced a while back during the last Nintendo Direct. The game is a multiplayer game where you pilot a tank to take out other tanks in a death match style battle. You have other modes to play and there is some single player content to sink your teeth into (like a introduction mission to get used to game mechanics) but overall, it looks like a fun little action game for the 3DS.
NintenDaan released the first 15 minutes or so of the game in action on his YouTube channel and visually, the game looks great. Having an art style strikingly similar to the Advance Wars series, this title looks to offer a really charming presentation.
If you have a JP Nintendo E-Shop account consider giving this game a shot!