Ok, I have found a simpler solution 
Being the idiot that I am I always over complicate things.
Technically this game should always/only end if the player runs out of bullets. No need for checking the targets at the same time. (As there should be no way all the targets are destroyed and the player is left with bullets, unless of course I over complicate things later down the road and introduce ricochets and other crazy ideas 
)
Since #bullets always == #targets, I can check just for bullets. In the EndLevel widget I can just count the targets left and determine if the level was cleared or not.
This works ok for now…
@Mind-Brain
if you see any issues with this code please let me know…
As always, any tips are greatly appreciated!