Okay, so subtlety is key here. What I've noticed about the show is that what draws me in the most about it is the realistic dynamic between the characters but also their reactions to simple things. "Beer'd ya" being "beard' me" in the other person's mind (even though they know better) is pretty great. The casual, relaxed tones actually remind me of Regular Show except interactions in this seem a bit further down - grounded, if you will - on a spectrum of personal interaction. "Less fanciful" is how I'd describe it but I'd also have to say "more charming". Now, it's not all realistic as we know that real people are often either stumbling over each other in a conversation or not really listening. The latter of this aspect is highlighted in Kit's disregard of Rav's insight but at the same time, it's not like there's an air of disconnection between them.
I know it looks like I'm reading too deep into this but really, I'm just trying to break it down into it's base components.
In summary: I liked it - even if it was short - and I found myself captured in a brief moment by characters who made me realize that other creations fail to do the same in twenty minutes or even more. Good work and may the winds of fate not screw you over.
P.S. Also, the concept of a civilization living in a cavity underground is so cool! Have an extra half-star for that.