I installed your plugin as a replacement for WPSQT. At first install went easy no errors or surprises.
It's easy to use, there are a few flaws to check though. For example the Add new Questions button should actually say Add new Answer.
Also there are lacking a few options, for style purposes only.
If you add The question title, this usually is already the question itself in the backend. Than you have the question field itself, which is a required field but if you put the question in the title you don't really need this field. Maybe you could change the required part so if people want they can leave it empty.
The message for the wrong answer, or right answer is usually the same for every question. It would be easier to have a Options page to remember these instead of having to add them in every question seperately :)
But this could easily become the best Quiz Plugin!