You can now make it required to answer a question.
You make a question required, by clicking it's Options button, and checking the required checkbox.
If the user does not answer a required question and clicks the Next button. The required question will change to red font, and the background will pulsate red, until the user answers the question.
If there are several unanswered required questions on the page, only the first required question will pulsate red. The second that question is answered by the respondent, the next required question on the page will pulsate red. This will continue until all required questions have been answered.
If a required question is hidden, by a "Only show when.." rule, it will naturally not be considered required.
Also just released:
You can now see geolocation information for your responses in the individual answers view, and when you save to disk.