How to get the Invincible Achievement/Trophy for Horned Knight

How to get the Invincible Achievement/Trophy

To get the Invincible achievement/trophy you must collect 7 hearts. You start each level in Horned Knight with 6 'Hearts', each of which represents a life. In order to gain extra hearts you must kill enemies as you progress through the game. Each time you kill an enemy a power bar will replenish up in the top left corner and once it has become full the next enemy you kill will drop a heart. All you simply have to do is collect it, pick up 7 hearts in this manner, and you will unlock the Invincible achievement/trophy.