Oh yeah, we walked around Manhattan and it was great. Nighttime was a lot fewer people than I would've thought for "the city that never sleeps", but then we randomly stumbled upon some guys freestyle rapping near Union Square (if I recall correctly), found a super weird grocery store that sold us alcohol at like 11 PM (in my country it's only legal to sell till 10 PM, after that only bars can serve and they can only serve open containers) (alcohol at 11 PM wasn't the reason it was weird, it was just... very different from everything else I'd seen, including in the US, interesting vibe lol - if I remember correctly, they had tables outside where we consumed said beer, so it was kind of a bar AND a grocery store? But I may be remembering wrong here)
Brooklyn was also pretty nice to walk around. The buildings were much prettier, and we also found random places to visit. Somewhere in Williamsburg there was literally like a mini music festival vibe place in an alleyway. Like multiple tents to buy drinks and at least one stage. No noticeable signs pointing to it IIRC, just a person who sold us a ticket at the entrance of the alleyway.
Didn't take much transit. Just the subway from our hotel near the airport to Manhattan or Brooklyn and then back at night. It worked fine, though wait times between trains were a bit longer than I'd expected for such a big city.