'Mission Complete/Game Over' screen once objective is complete.

I'm VERY new to using unity and would like guidance/assistance on how to create a 'GAME OVER' screen once objective is complete which is for the player to shoot down all enemy targets.

I have some knowledge on using gui, not much. Real problem is lack of coding integration, so would be great if I can get some help and how would I go about linking the 'GAME OVER' screen prior to objective being met.


Personally, I use this collider script - I'm doing a platformer though, so it'll be for touching the last platform.

function OnTriggerEnter(hit:Collider) { if(hit.gameObject.tag=="Player") Application.LoadLevel(2); }