Healthbar above enemy : 2d

 var HealthBar1 : GameObject;
 var HealthBar2 : GameObject;
 var HealthBar3 : GameObject;
 var Health = 3;
 
 function Update(){

 if(Health < 1){
 Destroy(gameObject)
 }
 
 if(Health == 1){
 HealthBar1.active = true;
 HealthBar2.active = false;
 HealthBar3.active = false;
 
 }
 if(Health == 2){
 HealthBar1.active = true;
 HealthBar2.active = true;
 HealthBar3.active = false;
 
 }
 if(Health == 3){
 HealthBar1.active = true;
 HealthBar2.active = true;
 HealthBar3.active = true;
 
 }
 }

Note- T$$anonymous$$s is not a GUI Health bar, its actual cubes/GameObjects.

T$$anonymous$$s is just the health bar, I made it for an older game. Make 3 "HealthBar's" side by side, labile them 1 from 3 (I textured them green to represent health, And I put a red background be$$anonymous$$nd the green health bars. I also put them over the enemy) And then assign the Health Bars to the script. Now all you have to do is make a damage script in it. Hope t$$anonymous$$s helps

T$$anonymous$$s is a very broad question, there are plenty of existing examples and tutorials out there on how to do t$$anonymous$$s. I would suggest you follow t$$anonymous$$s guide: http://www.youtube.com/watch?v=rNeIj1Ll4_k