Fill Magic to 1/2
If you need some magic but only have a a little left, go to the blacksmith shop, hammer down the stake and drop down the hole. While down there go up to the door way above you and there should be a green thing holding a pot.
With the little magic you have sprinkle some magic dust on it and a weird creature will emerge. He says that will reduce your magic to 1/2, but if you have less than that he will fill it up to 1/2.

Get the #4 Sword
In the dark world, when you are on your way to get the 7th crystal, up in the cave you must go through to get there, there is a little guy who says he lost his partner, and he will reward you if you can help him find him. Well his partner is the sword mender in the light world. So lead the little guy to his partner, and give them your sword. They will mend it for free for you.

Get the 4th Magic Jar
Beside the desert in the light world, there is a man who sits by a sign and he says to leave him alone. When you are nearing the end of the game in the dark world, in the village in one of the demolished houses, there will be a chest. You can't open it, so bring it to that guy in the light world who wants to be left alone. He turns out to be a theif and he will pick the lock for you, and inside the chest is the last magic jar.

Get the Magic Powder
In the light world, when you are in the dark forest, you will see a rotted mushroom, you are allowed to put it in your item stash. It doesn't do anything, but take it and go to the witch who is brewing something beside the potion shop. Give the mushroom to her and she will say that she will give you something in return. So go in the shop, and beside the little guy sitting there, is a bag of magic powder.

Items from the Fat Ferry
Near the end of the game in the dark world, you will see in the pyramid that there is a crack in it for a bomb to blow up. An ordinary bomb wo'nt do the trick, but a super bomb will.
Go to the guy near the village selling bombs. He will have a big green one to sell to you, go and buy it, but be carefull, since it is so big, you cant carry it, you have to drag it to the pyramid.
When you get to the pyramid, releace the bomb in front of the crack. It will blow a hole in the wall. Enter to meeet the fat fairy who will tell you to throw items into the pond. The only items you can throw in are your master sword, your outfit, and an empty magic jar. She will give you a #3 sword, a #4 outfit, and fill your empty jars with magic potion.