1.LoZ:The classic NES game, Zelda just so happens to be my opinion of an extremely confusing game. With a pretty expansive map and mandatory hidden objects in one tile areas, it's hard to find anything. Really garbled text, slow progression, and an insane final dungeon and boss that are impossible to beat without max level gear and the silver key make this game for diehard gamers only. Combat is actually relatively easy after a bit of getting used to however.
2.AoL:With sidescroller mechanics, most atttacks are unavoidable and deal massive damage. Combined with a learning curve and a confusing overworld, this game is by far one of the most difficult games in the Zelda franchise if not one of the most. However, a few grinding spots can make the game a bit easier and the screen format leads to some glitches that can allow a much faster game.
3.SS:I didn't enjoy Skyward Sword and all the hype that came with it. Motion controls, mixed with really weird walking controls makes for a nightmare of a game. Take off the motion control and this game might be 10th place.
4.OOA+OOS:The constant switching makes it a long game, and the long dungeons aren't hard but take a while.
5.ALttP I don't know why people are complaining about this one's combat, it's more avoidable than AoL. The puzzles are cake.
6.MM:Great game, but I felt that it was too rushed. Personally the second and fourth temples dragged on for the equivalent of two temples in OoT. The puzzles were difficult, the combat was easy, the moon countdown doesn't really bother you, but the sidequests are numerous, and certain parts of the game are confusing, such as the Garo Mask quest.
7.TP:Easiest combat ever...the puzzles in all the dungeons were hard. With an extraneous beginning and and easy endgame, this one is not to hard to beat. I hated Stallord for being...annoying....
8.OoT:The start to 3D Zelda games was fun. With puzzles slightly easier than MM and TP. Bosses were a piece of quiche and early game was too easy.
9.WW:The small amount of enemies, slow enemy attack rate, and overall combat system makes fighting almost nothing. I can see the creativity put into the bosses. The only difficult part are the average puzzles and pathetic exploration.
10.ST:Easy combat, hard puzzles, and I like trains, the weird 2 screen gameplay didn't really help.
11.MC:I enjoyed playing this on as a kid. Looking back on it, it's still enjoyable, but not hard. The puzzles involving clones were easy, and most puzzle elements and items were practically forgotten into the game. The game was short and the only hard dungeon was the last, with a ridiculously hard boss and simple puzzles that are difficult to execute.
12.TH:It's a pitifully easy and short game with simple combat and simple puzzles, but I'm giving it one rank higher due to the fact that your progression is also determined by two other (strangers') players' collaboration.
13.LA:Crap story, crap combat, crap items, and the almost nonexistent puzzles make this game crap, enough said.
14.FS:..What do you expect from a non-open world exploration game? This game is an odd egg, and easy to complete compact with not so difficult combat, and average puzzles.
15.FSA:Same as the first installment but worse.
16.LbW:The puzzles were OK, but the short game and easy combat made for a weak game.
17.PH:Way easier than its cousin WW, was only tough for 20 minutes, the rest of the game was jello.
BoTW:???Let's just wait and see ^
If think after that Majora's Mask or the first Zelda, which just didn't gave you any clue what to do, and level 9 is indeed brutal. Fourth place is A Link to the Past. Those four are certain for me, however, after those I don't know anymore, it changes, and as I got better understanding the English in the game (when I was young I just skipped many textboxes), I discovered many new things, before then every Zelda was hard 
