i like the ghost effect when you are low on health, though gameplay wise it is a bit dull,
you can basicly groop them all together in a big open room by running around then and recharging then when you have all of them go off exploring with out a care in the world which detracts from the creepy atmosphere.
a solution might be to move only ones with in a certain range or changing the ghosts speed depending on there distance to the player, closer being faster and at a certain range they dont move at all.
also you could add a flicker to the flashlight as it gets dim, as if it is about to go flat. and the flashing will be a better reminder that you need to recharge. and add some stress to the gameplay
also more levels wouldnt hurt