Great work so far, MadPXL!
I really think, the Ice Cave does not work. The toches right at the ice wall? Shouldn't they melt? Ok, small thing, but if you have torches, they should be in a seperated candelaber or just use light from the outside (I think Zelda did it that way?). The other thing is the just recolored underground. I don't think this work. Ice has a complete different texture/material than stone. You should remake the underground for every world I think.
The rupee should have more contrast, the side is barely recognizable. I'm not sure how good the NDS screen is, but the GBA screen is pretty bad afaik.
Keep 'pushing!