You can pull hearts out with the Divine Punishment ability. However by leveling up, you will have multiple animations and only the first one will qualify. You must stop leveling up and farm for Holy Heart immediately. Consider stopping at level 5 and never finish it. Restart the level before time out in order to avoid gaining experience and leveling. Restart the level as many times as needed. Note: Start the level with the stick weapon, as it is cheaper and more efficient because the goal is to stun and not kill. Keep stunning and using Divine Punishment until the point where you will be overwhelmed by enemies. At this point, use the shield found in the right side crate in the lower side. Upgrade only your health. Leveling up strength will only result in enemies getting killed faster, lowering the chance of stunning.