Yeah, Zelda II is a good game, but it's a HUGE step down from Zelda I. I was thinking about that as I played. One of the major things is how in Zelda I, there are tons of little hidden things you might find or might never find (bushes to burn for rupees, seventeen heart containers scattered about, holes to bomb, gambling pits, the whistle and raft and such actually doing multiple things). Whereas in Zelda II, you find the raft solely so you can use it at one particular point and advance the game. You find the whistle solely so you can use it at another particular point (well, two) and advance the game. There are only ummm four (I think) heart containers to find and you need every one to win. very few secrets. etc.
I probably had to do the Road to the Great Palace/Great Palace five or six times before I had it down. Then, on the last run, I ended up beating the game with two extra lives to spare. In fact, I beat the thunderbird/butterfly guy with no magic and a single life box left, expected to die on the shadow and be able to fight him with full life/magic, and then beat the shadow without taking a hit (no idea how I pulled that off).