Great quiz, but you need to make it easier to tell the guessed from the unguessed, particularly the squares that are mostly over water. I couldn't tell that an answer was needed for Honolulu, Lisbon, San Juan, or Cebu, else I would have gotten them.
Thanks for the feedback! I personally think the squares are easily identifiable, though I will change them if more people tell me otherwise. I did spot a mistake with the Cebu square though, it was triggered by another answer, so it was shown as guessed even though it wasn't. It's fixed now, the changes should be up soon.