first of all i dont know which ones you found so i am tellig you where all of them are,
the first 1 is in the first stage first level just behind u fight the first demon theres a
ladder and next to it theres a grave stone use the gorgon magic for it the second in the
death castle (2-2) where you fight those electrical dragons and those brain looking things
right on the left upper corner u need the angel armor to get there the last on is on the
sea of death (3-2) once u pass the wall that moves there will be an opening on top go
throw there and you will find a part with spikes on both sides of the walls pass throw
there with the dragon shield and there will the door. hope it helps and answers your
question.