Zelda no Densetsu: 4tsu no Tsurugi+

In the level Infiltration of Hyrule Castle, in the Near the Fields area, get caught by the spotlights. Fall down the hole and get the treasure chest and boomerang, etc. then go to the final cell (the one with a lot of pots and several switches). Get in a line and shoot your boomerangs, and you'll get a lot of Force Gems. Now, DO NOT GET THE HAMMER. Leave through the southern door, then go back in and get the Force Gems from the pots again. Repeat as much as you want.

After you talk to all the spies in the level and return to get the shovel, go back into the shadow world and switch the shovel for another Pegasus Boot or the empty item stand. Leave the shadow world then the area with another item other than Pegasus Boots and go back down into the Dark World. The passage to the shovel will be blocked and the kid won't open it again. Talk to him and he will give you Pegasus Boots and you'll drop the other item. Keep picking up the other item and talk to the kid again for an infinite supply of the Pegasus Boot.

On the level Infiltration of Hyrule Castle, in the Near the Fields area, if you get caught an extremely large amount of times, there is a chance that your Links will turn invisible. There is also a chance that the sound of the game will go away. This does not affect the gameplay.