Bomb for Shmup Game

Hi, the core game kit is a very helpful tool but I am stuck with realizing a virtual bomb that kills all enemies on the screen. - I have already a solution with a gamecontroller by pressing the 'b' key but I wonder how to realise it with the core game kit. Where can I hook in the getKey 'b' and where can I update the the Worldvariable with -1? - Also where should I put the Killable on when the bomb itself is only virtually - as I understood I would need one. - Also I tried to update the world variable for the Bombs in the script but it does not update, I can read but not write. Only my old variable from the game controller is updating. I can see the World Var with a listener. - Here is the code from my gamecontroller:


private int bomb;//not the worldvariable

void Update ()

{

var variable = WorldVariableTracker.GetWorldVariable("Bombs");
//the world variable
bomb = variable.CurrentIntValue;
// my var can read


if (Input.GetKeyDown (KeyCode.B) && bomb > 0) {

BombeSchmeissen ();

bomb--;

bombText.text = "Bomben: " + bomb;

variable.CurrentIntValue -= 1;
// does not update
}

public void BombeSchmeissen () {
 // Releases the Bomb


if (bomb > 0) {

enemies = GameObject.FindGameObjectsWithTag ("Enemy");

Instantiate (bombenExplosion);

foreach (var enemie in enemies) {

Destroy (enemie);

}

}

Would be great to hear the solution.

Cheers