Let's identify the compositional techniques used in Animal Crossing: New Leaf - K.K. Slider's New Song in D Minor to enhance the gameplay and visuals! Please refer to the following video:
K.K. Slider is a dog who performs compositions at Club LOL. His formal name is Totakeke, which is a variant of the name Kazumi Totaka, one of the composers for the game. When Totaka-san's name is listed as Totaka Kazumi and then Totaka K., the name sounds like Totakeke!
K.K. uses the D harmonic minor key with a #4 in this theme to create a mysterious mood. When performing, K.K. Slider seems to play contrasting pieces in order to keep things interesting. If he played all the songs in G Major, for instance, the music would most like not be as engaging unless there is a crowd who loves minimalism or is there for a G-Major-themed show.
The use of the augmented 2nd appears in other themes such as the Prince of Persia Intro theme, the King's Quest 6 Village Theme. Simon the Sorcerer Town Theme, and more:
The King's Quest 6 VillageTheme begins at 10:22: