This is “Shop” from the RPG “Undertale” by Toby Fox.
This is composed by him as well.
The melody used in this song can be heard in various scenes throughout the game.
I think this strengthens the overall sense of unity in the game. (It seems Leitmotif)
The chord progression is a simple diatonic chord.
In the middle part of the song, the so-called “Ohdo progression(王道進行)”(IV-V/IV-iii-VI), which is very popular chord progression in Japan, is used(around 0:25~0:37).
I hadn’t imagined that a chord progression like above, which is obviously emotional, would be used overseas.
But Toby Fox played a lot of Japanese games like “MOTHER” and “Super Mario RPG”, so I think that must have influenced him. (Interview article Note: Japanese only)
Also, it seems trying to minimize the movement of notes due to chord changes.
In the the above section, the bass and the notes above it barely move.
I think the combination of dynamic chord progressions and restrained movements creates a joyful yet calm atmosphere.