Truly the only gripe I have about it is that that in the cafe area, when you toggle on the cafe background sounds - the audio used is a recording of an actual cafe that has it's own music playing in the background, which happens to be "What I Am" by Edie Brickell & The New Bohemians. And the only reason why I know that is because it's a song that played a lot while I was growing up, and my brain latches onto the very faint but still present sound of the song! This is such a niche complaint, and yet it makes me not want to be in the cafe when I'm focusing because then I'm hearing the chorus of that song on repeat every few minutes. But I love being in a cafe environment where I can hear muffled voices coalescing into a soothing hum.
And one idea I had that would be cool (but obviously not necessary) is the option to have a community board where folks can leave notes being like, "I'm prepping for a test, if anyone who has knowledge of (topic) could meet me in my burrow to help me study!" or something similar. And then allow an option for voice-chat in those scenarios (where they are in a burrow of their own, co-working on a project) and can talk in real time about the project they are working on. I think it would work best if the open voice-chat was limited to only burrow spaces, and is only an option opened up if the person who's burrow it is is there and has the chat option toggled on.