Zelda 3: Hearts
Go into the Lost Woods just north of the Furtune Teller's hut. Proceed north. You should see a 3x3 bush. Cut the center bush and drop into the hole. The heart piece should be just below you.
Bomb through the craked wall in the basement of the Thieve's Hideout. There is a piece of heart in the chest.
Drop in the Well.
Northwest of the bottle merchant in Kakariko Village is a well. Go to the ledge above and drop into it. Inside, bomb through a cluster of rocks to find the piece of heart.
15 Second Game.
Outside of the house of the Quarreling Brother's, you can play the 15 second game. If you can complete the maze in 15 seconds or less, you will win a piece of heart.
Inside the Watergate, in the far room, pull the lever on the right. This causes the dam to open, lowering the water in the swamp region. Exit the Watergate and there will be a heart piece just to the west of you.
Enter the cave in the Northeast corner of the Great Desert. In the room with the Wise man, bomb through the south wall. Inside is a chest containing a heart piece.
West of the Sanctuary.
Using the Pegasus Shoes, dash into the pile of rocks west of the Sanctuary. Go down the stairs that were under the rocks. Inside is a small chest with the heart piece.
South West Desert Corner.
Go into the desert palace. Exit throught the western exit. Stay on the ledge and head south. There is a heart piece at the end of the ledge.
Southwest of Zora's Falls.
Once you get the flippers, head south. Go over the first waterfall and head west just before going over the second. Walk up a small grass slope and continue west until you come to the heart piece.
Drop from Spectacle Rock.
Walk around the left side of the rock formation in front of Spectacle Rock. Drop over the edge onto the ledge. Go into the cave and go to floor 2F. There it is.
The first time you warp back to the light world with the magic mirror, you should be ontop of Spectacle Rock. A heart piece awaits for you.
After Agahnim has been defeated, dash into the Strange Tree. Drop down the trunk. After climbing the stairs, go to the right wall and bomb through it. A heart piece is inside.
Pyramid of Power.
From where you first appear in the Dark World after defeating Agahnim, walk down the first set of stairs and then down the stairs on the right. Continue right and drop off the small ledge. Go up and around to find the heart piece.
Lake Hylia Circle of Stones.
At the northwest corner of Ice Island, there is a large circle of stones which you can swim to. Stand inside of the circle and use the magic mirror to warp back to the Light World. You will appear on an island with the heart piece.
South of Haunted Grove.
There is a small circle of bushes just south of the Haunted Grove in the Dark World. Stand in the middle and use the magic mirror to warp back to the light world. Enter the cave on the small plateau to find a heart piece.
The Digging Game.
In the same spot where the 15 second game is in the Light World, the Digging Game is in the Dark World. Pay the gatekeeper 80 Rupees and keep trying until you find the heart piece.
North of the Cemetery.
Link can climb up the short ladder which is located on the north side of the cemetery in the Dark World, but it looks as if there's nowhere to go from there. Use the Magic Mirror to warp to the Light World and then enter the cave which appears in front of Link. Bomb through the far wall to find the heart piece.
Person who Wears the Cape.
A sign reads: "I'll give a Piece of Heart to the person who wears the Cape." You should be able to see it from here. Enter the cave and go to Floor 2F. Use the Hookshot to cross the hole and then use the Magic Cape to walk through the Bumper. Walk out the door to find the heart piece.
The Chest Game.
Enter the hut with the symbol of a chest above the door in the Village of Outcasts. Pay the storekeeper 30 Rupees and play the chest game. Keep trying until you find the heart piece.
Pound the Stakes.
Just south of the Smithy in the Dark World are 22 stakes in the ground. Use the Magic Hammer to pound down all the stakes. When all the stakes are pounded down, the tree stump below the stakes will disappear and an entrance to a cave will appear. Enter to find the heart piece.
West Misery Maze Entrance.
Warp to Location 6 and then use the Warp Tile which is located under a heavy rock. Jump off the ledge and proceed directly north. Go straight into the west mouth entrance and proceed down the stairs to find two chests blocked by stones. Push the stones away to get into the chests.
Northeast Corner of Misery Mire.
There is a short (really short) dead end type of thing in the upper eastern corner of Misery Mire in the Dark World (i really don't know what else to call it). Stand in this area and use the Magic Mirror to return to the Light World. Walk south and lift the large stone you see. Go into the cave entrance that was under the rock and push the blocks to get the heart piece.
Travel west from Turtle Rock. Lift the first large rock. Link will find a cave with platforms, Chests and Skulls. Go up and over the invisible bridge using the Cane of Somaria as a guide. Continue until you find yourself outside.
Narrow Ledge on Death Mountain
Before entering the right door on the narrow ledge outside of Turtle Rock dungeon, use the Magic Mirror to warp. Enter the cave and defeat all of the enemies. Go through and open the door.