Countries that don't recognize dual citizenship

Fun quiz! However, I feel like there isn’t enough time. Maybe add an extra minute or so?

Not sure why this list is only partly in alphabetical order, probably needs rearranging. Also it appears dual citizenship has been allowed in Djibouti since 2004, Tonga since 2007, and Zimbabwe since 2013 and is allowed in Papua New Guinea and Tajikistan for limited other countries. Venezuelans can have it but need to leave and enter on the Venezuelan passport and Thailand appears to have no law specifically stopping it, so should be off the list.

Also from my research the following appear to not allow dual nationality and need to be added in: Afghanistan, Brunei, Cameroon, DRC, Eritrea, Estonia, Georgia, Guinea, Guyana, Kiribati, Liechtenstein, Madagascar, Malawi, Montenegro, Sao Tome and Principe, Suriname, Tanzania and Togo. Of those, the exclusion is only for naturalised citizens in Estonia, Kiribati, Malawi, Sao Tome and Togo. Liechtenstein does allow it but only if you get the second citizenship after the Liechtenstein one.