I'm glad you're enjoying it! And I wish I could snap my fingers and add animations for black random NPC guys into the game, but it's hard to describe just how hard it is to find an equivalent animatino for everything the random NPCs have, I didn't want black male npcs to have white guy standard porn animations. And not all the actresses even have scenes with black males sadly.
I downloaded several games out of curiosity, boredom and interest in the human nature, (i do creative writing and am thinking of writing a text-based game if i can manage to learn how to code that is). I stopped most of them after a few minutes.
Yours is the first game about transformation that i find good! it's well written and thought.
The sex dynamic are good, the variety of npc behaviour too. The best part being that you can have fun wearing both bodies...
As for the BBC, one thing you could do is to add some line of dialogue: the blonde girl could talk about bbc with the FC. And challenge the MC once she likes him enough "if MC make cum as much as her black lover they can become fuckbuddy but if you loose you'll have to use the newu machine, or a pill and while looking like me experiment what it is...
You should add the possibility to randomly meet one's lover at the beach or the mall.
More interaction btwn MC and his female lover, i managed to have two of them to like me (more than 20 points if i recall and no changes...). Same with the male NPC (unless it already exist, so far i reached something like level 8 with one of them).
More talk btwn MC/FC and NPCs about the pill too.
A suggestion: each new citizen could be offered a one day pill for free (to claim within a week) so they could better appreciate this city's way of life, with a voucher or money if they do take it in front of the pharmacist.