Concept Art
Prior to the final animation, several character designs were explored. As a part of the animation featured a carefree character walking by, it was important for the character design to be simple to animate and exaggerate. After going through several sketches, the final design chose likened a "marshmallow", being bouncy and energetic in their movements. Following this, all elements within the animation also have some element of bouncing or squishing, even when standing still. 
Music by Hard Boiled Kevin MacLeod ( Licensed under Creative Commons: By Attribution 3.0 License 

Sound Credits (from 
Flush by Panska Koprivikova Klara 
Bubble-tiny by cdonahueucsd 
tone-beep by Pan14 
Bubble-5 by Glaneur de sons 
Car-horn-beeps by hsaunier10 
Train-accelerating-away-clip-clop-a by InspectorJ 
Elevator-ding by xfixy8