The Village Idiot
Since Fly Head is a stick figure, unlike heat guy, can we pay attention to Fly Head?
Affix black hole head propeller to the front of a drill tank in such a way as to continually pull the drill tank forward through the center of Russia. Keep close to this drill tank.
Continue throwing drill tanks.
The now black-hole-powered drill tank will retain its speed after pushing through Russia, allowing you to continue your slew of drill tanks on the far side of it, preventing thunderhead from being able to block everything, and still keeping him distracted from you, who will be driving the black-hole-powered drill tank straight into his face.
Death by black hole has worked on the others, so why not on him?