In area 2, bottom center 10x12 puzzle is unsolvable by logic only--there are multiple solutions, some of which the game considers incorrect. I checked with a picross solver to make sure. (see image) 
Solver: teal nonogram solver
3 years ago(+4)
I believe the 15x15 has the same issue, this is as far as I could get logically. Ran it through the solver and it got just as far.
[SPOILER]
[SPOILER]
The issue appears when I try to force it further:
The resulting puzzle cannot be solved!
I believe the 15x15 can be solved by guesswork, but unfortunately not by pure logic.
3 years ago(+1)
With that all said, this is an absolutely stunning game, and easily the prettiest picross I've ever played. Thank you for combining the city-builder aspect with a puzzle so well!