Spain and Kuwait are missing. Kazakhstan and Tajikistan are spelled wrong. Not sure if you included the Ottoman empire as Islamic but that would mean you need to add all the Balkan countries.
Excluding the Ottoman times, when was any part of Bulgaria under the authority of the Caliph? This quiz seems to include only Umayyad/Abbasid Caliphate holdings, so this strange inclusion should be explained or removed! Otherwise, very good quiz.