First off: Thank you for remixing the credits. Seriously. I don't understand why that song isn't more popular.
Second: You should really expand upon each theme more. They flow into each other pretty well, so maybe you shouldn't mess with the arrangement of the first part, but I'd like to see you mix the themes a bit more liberally in the second half. Maybe try to pull them all together in an interesting way.
And yeah, there are still some problems with sound quality, but I'm no expert on that, so I'll leave it for someone else.
That said, I really enjoyed it. I'm a big fan of the Gameboy Zeldas.