Pretty fun game. Addicting, and makes failure feel like it's the fault of the player, not the game. Spritework was good, and the music has that old Squaresoft sound. But a few issues stood out.
1. The gates look a lot like ladders, which confused me the first time or two I interacted with them. But the chains were worse. They looked like part of the background and not walls. Every time I started a stage with a chain wall I tried to run past them again.
2. There was no way to adjust your horizontal positioning by just a couple of pixels. Inching forward or making a small correction to a jump was impossible. An instant tap of the directional key causes the character to move 5 or 6 whole pixels, which is annoying with all the precision jumps the player is expected to make.
3. Maybe this was just me, but the water boss seemed much harder than the fire and grass bosses. I died on the latter two a total of about ten times put together, but I must have died 60 times on the water boss because of all the single tile platforms.
(There was also no music the first time I started the fourth area. Just a small glitch I thought I'd mention.)
All the above is pretty minor, and I'd probably give the game the full five stars were it not for the Wind Waker bullshit padding telling me to go back and find some keys. I elected to stop playing at that point. Had it been to unlock some secret or achievement I may have tried it. But blatantly barring progress for cryptic backtracking is unacceptable.
Still a really solid game. Good work in general. I almost finished this one ( I assume) and I usually lose interest in browser games after a minute or two.