This achievement is really not too hard, just a bit time consuming. There are 21 missions total in the game. If you die, you simply respawn right where you were with no penalties towards progress. Simply beat all 21 missions on Emergent, or Medium. If you complete the game on Singular, or Hard, you will also get this achievement. If you beat the game on Hard or Medium, you will also get the achievement "Autonomous", for beating the game on easy. If you have any questions, feel free to ask!