Fog working on my machine but not on others? /how to flash a colour on the screen

So I've got a 2D platformer and I'm using fog to show a player taking damage and dying.
I call this function when I die:

 void die() {
 
         Sprite spriteDude = GetComponent<Sprite>();
         
         RenderSettings.fog = true;
         death = Time.time;
         direction = 0f;
         grounded = false;
         dead = true;
         Debug.Log("DEAD");
         
         spriteDude.PlayClip("char2(DEAD2)");
         
     }

And this if statement is in my update function. fogRed is a float which starts at 0.7

 if(dead){
             
             RenderSettings.fogColor = Color.red;
             RenderSettings.fogDensity = fogRed;
             fogRed = fogRed - 0.05f;
             
             if(Time.time >= death + 0.6f){
                    Application.LoadLevel (Application.loadedLevel);
             }
         }

For some reason, when I run this on my laptop it works no problem but the fog doesn't show up at all when I send it to others. Any ideas as to why other people don't see any flash of red at all, no matter how dense I set the fog. Or any other suggestions (in c#) as to how to make the screen briefly flash red and fade out?