I had a few ideas for an enhanced remake of the original Legend of Zelda on 15 MHz calculators. Maybe "remake" is not the appropriate word, so much as a rendition, or watered-down port with a few enhancements.
The plot and flow of gameplay will be slightly different. As opposed to Princess Zelda separating the Triforce of Wisdom into 8 sections and dividing them across several dungeons, Link's task is to find each whole piece of the Triforce in order to break the seal on Princess Zelda's prison within Ganon's Citadel. This doesn't necessarily limit the game to three dungeons - there will be dungeons where important items are guarded by bosses. It it necessary to procure these items so Link can reach other sections of Hyrule and ultimately uncover the Triforce. Some dungeons will also have seals that require to specific Triforce pieces to be in your inventory.
I've cut down on the number of items present in the game. It's rounded down to four equippable items, (Link may only equip a single item at a time) four "quest" items - or items that have passive effects - and of course Link's tunic and shield. The complete inventory is:
Wooden Sword (L1) - inflicts 1 point of damage against enemies; some enemies are immune to this sword
Magical Sword (L2) - inflicts 2 points of damage against enemies
Wooden Shield (L1) - blocks very few projectile attacks (but cannot be eaten by a Like-Like)
Magical Shield (L2) - blocks most projectile attacks (but can be eaten by a Like-Like)
Hylian Tunic (L1) - does nothing (it's simply your default tunic)
Hero's Clothes (L2) - halves all damage inflicted against Link
Magical Bow - fires arrows that allow Link to penetrate some enemy defenses (each arrow subtracts 1 rupee)
Bombs - can damage multiple, adjacent enemies, or destroy weak objects; (walls, blocks, etc.) Link's initial bomb capacity is 8, but it is possible to purchase an upgrade to 16
Switch-Hook - when fired at an object, Link switches places with it; (this is effective against enemies or movable pots) stuns enemies that are too heavy to switch places with Link; will grab objects such as keys or rupees and add them to Link's inventory, as opposed to switching places with them
Giant's Ring - allows Link to push certain types of blocks
Fire Arrow - allows arrows to light torches
Flippers - allows Link to swim in watery areas
Water of Life - when Link loses all hearts, this will automatically restore 3 of them (and then vanishes from his inventory)
I haven't designed any maps yet. Since the sprites will be 16x16, I was thinking of doing 8x8 map tiles. Each of the boundaries around each action screen could be composed of 8x8 sprites that only show halves of trees and mountains, which should help prevent any given screen from becoming too cramped with large objects. Tiles within the boundaries would still make 16x16 px objects. Each action screen would only be 96x64 pixels.
Link's status is also a bit different. I thought only 8 total hearts would be sufficient. (3 to boot) There may be more than 5 Heart Containers to be found, and I say this for two reasons: 1.) Games like Metroid did this with Energy Tanks, in case the player did not discover them all; and 2.) There will occasionally be situations where you will lose a Heart Container. (i.e., the "Leave your money or leave your life" choice in some rooms)