Well, I thought I would take on this quest since it won the voting by such a healthy margin. And after the impression it left on me all I can say, is "How did I miss this?" The best answer I can think of is that it got lost in the shuffle of the more "revolutionary" quests of its time like LEXX, Mario's Insane Rampage, Mega Man Dr. Wily's Revenge, etc. Link's Birthday DX presents as outstanding of a gameplay as I have experienced in a long time. I agree with russadwan on pretty much all of his points, but as I have now played through Level 7, the Fire Water Dungeon, there is room to say more. (Personal note: it would have been awesome if Mr. Z had decided to call it "Fire Water Burn.")
At the beginning of the quest, the amount of ground you can cover is very limited. As you get items in the early levels, the territory available to you opens up, little by little . . . . and you begin to wonder how much you could do if you only had a certain key item, such as the Hammer, or the flippers. Upon progressing through the levels in the 4 - 6 range, the exploratory possibilities simply explode. You have to take careful note of places you couldn't get into when you first reach them, both in the overworld and in the dungeons, since the acquisition of a critical power-up will let you through once you go back there. This is a very mentally engaging quest.
After you beat each level, Zelda tells you where to find the next one so you're never hopelessly lost. In addition to the regular levels, there are bonus levels and mini-dungeons scattered everywhere. Some of them hold rewards that are more important than others. Note to future travelers - - Fire Gleeok + White Sword = PAIN. Just something to keep in mind right before it is time to hit level 7's boss room.
