One more thing regarding the difficulty - burning the present to increase fire give you way bigger area to explore/run which also vastly improves your chances of survival as avoiding enemies is much easier. Sometimes leveling the fire is more impactful than leveling skills. You just need to watch out for the dark thingy that tries to destroy the fire once it notices that it leveled up :)
I prefer to quickly level up the fire and than immediatelly reach the next present that you now have access to due to the increased play area.