True Spartan is an achievement/trophy in Metro Last Light. It is awarded to the player after completing the level D6 without dying once. If you do die, you will need to restart the level. The achievement/trophy should unlock after the flamethrower heavy is dead, before the armoured train breaks through the wall. It is pretty easy as long as you take cover most of the time. It is best to do this on a low difficulty. Below is a video guide if you are having trouble.