The first dungeon shown above is simply known as 'Taiko no Tatsujin Muzukashii' (which means that there probably are also the easier Kantan and Futsuu versions too). After facing some of Taiko 3DS's generic enemies, the boss battle is against Don-chan and Raruko. (just look at Raruko's eyes, it's so hilarious)
The 2nd video shows the Oni dungeon, featuring more battles and Don+Raruko again as bosses, this time with an extended life bar (probably due to the Seven Orbs' power).
