City of Octopolis: The bassline with the organ-y instrument certainly work together to give an underwater nightlife vibe. This is a great city theme and would definitely work for a JRPG as you describe. Something that I thought was really cool whether or not it was intended, there is an instrument that plays from the beginning that is difficult to identify, but it serves as a percussion instrument pounding 8th notes that I imagine as an octopus slamming all 8 of its arms on a table or dealing out 8 cards at a casino poker table or something. I think the bubble SFX are tasteful and add to the ambience without distracting. I like the slow down at the end of the loop which makes it feel like maybe the night is coming to a close, but then it starts right back up again like a city that is constantly bustling.
Did I imagine the city?: I certainly did! I like your textual imagery guidance for imagining a night city with glowing crystals underwater, but I think you did a great job of conveying all of those aspects in your music and a similar image would have popped into my head even if I had not read the description ahead of time. Overall nice work and thank you for sharing!