Source: Wikipedia, "Black Heart", available under the CC-BY-SA License.
Black Heart is a horizontally scrolling shoot 'em up arcade game released by UPL in 1991. The player controls a fire-breathing dragon and shoots enemies with fireballs, collects power-ups, and defeats bosses to advance levels.
Taking place in a magical world, the people of the world relish in a time of peace they've maintained for three-hundred years. However, Taranis, the leader of the Black Magic Military, starts a world war when he suddenly attacks the White Magic Military. The attacks continue and the Black Magic Military is on the verge of victory. The only hope the magic world has to stop Taranis lies in two fellow Black Magic users and dragon-riding soldiers of the Black Magic Military, Giroux and Jeanne, who betray Taranis and rebel against him in order to seek peace for an unknown reason.