While I have not played an original NES game in a long, long time, I still cannot forget how wonderful it was to actually beat "The Legend Of Zelda" on my own five years after I had first played it. If you own an original NES but do not own this game, then you need to pay the $... (which is small beans considering it used to cost about $... back in its original 1987 release) and keep it in your NES for about two to three months until you defeat Ganon.
This game is incredible because of its immense challenge in all aspects. Perhaps the hardest part of this game is finding the nine dungeons (preferably in order) in which to defeat your main enemies to find the pieces of the Tri-Force. Besides your first "gift", a wooden sword, and believe me, it is a gift considering how difficult it is to find everything else, you will have to spend intricate time surveying every piece of land to truly be a Zelda genius.
The coolest part of this game is the musical score. The quick medieval music instantly drags you into the theme of the game and will keep you enthralled for a long time.
One little tip: when you eventually get into level 9, watch out for the room that will trap you in on all sides. Otherwise, you get no more help from me.
Peace and buy the game!