HAHAHAHAHHAHAH!!! I BEAT CHALLENG 4!!! HAHAH!
heres how i did it!:
have shield follow sword
have sword circle around the outside of the ring so that following shield is always slightly closer to the center thus as dragon trys to kill you he will fire at shield, so sence sword is ahead of shield you have a few seconds to fire at a wack till dragon move out of range.
repeat till dragon.
is ded! DED i say!
D E D!