I know there are lots of ways to trigger the end of a game but I am wondering how to end the game when all enemies are dead or you run out of bullets rather than walking into a trigger.

Here is the scenerio. A hunting game. Player does not move, he is like a turret. There are entities (ducks) using dumb ai that fly around the level. Player can shoot them. when all ducks are dead game ends with a splash sceen that says you win. If you run out of ammo before all ducks are dead game ends with a splash screen that says you lose.

Any idea how to script this?