gistfile1.txt

using UnityEngine;
using System.Collections;

public class EnemyHealth : MonoBehaviour {
	
	public float hitPoints = 100f;//max health
	public float currentHitPoints;//current health

	public GameObject destroyFX;//not sure why you use GameObject rather than Transform...
    public GameObject healthbar;

    public Color32 startColor;
    public Color32 middleColor;
    public Color32 endColor;
	
	void Start () {
		currentHitPoints = hitPoints;//starting health, which is max health
	}
	
	void TakeDamage(float amt) { //amt=amount of health
		currentHitPoints -= amt;

        //float healthCalc = currentHitPoints / hitPoints; //if currentHitPoints 80 / 100 = 0.8f //this will decrease the healthbar when taking damage
        //setHealthbar(healthCalc);
        setHealthbar();

        if (currentHitPoints <=0) {
			currentHitPoints = 0;
			Die();
		}
	}
	
	void Die() {
		if(gameObject.tag == "Enemy") {
			//Instantiate(destroyFX, this.transform.position, this.transform.rotation); <- need an explosion! not sure why we need keyword: "this."
			Destroy (gameObject);
			//Debug.Log ("Enemy Object Has died");
		}
	}

    public void setHealthbar (float enemyHealth) {
        //enemyHealth valve 0-1, <- health goes from 0=0% to 1=100%?
        float healthCalc = currentHitPoints / hitPoints;
        healthbar.transform.localScale = new Vector3(enemyHealth, healthbar.transform.localScale.y, healthbar.transform.localScale.z);

        if (healthCalc < 0.5f) {
            healthbar.color = Color.Lerp(endColor, middleColor, healthCalc * 2);
        }
        else {
            healthbar.color = Color.Lerp(middleColor, startColor, (healthCalc - 0.5f) * 2);
        }
    }

}