The overworld map is brilliant. However, the 1/8 heart increments seem half baked and too ambitious. Change it to 1/4 increments like the future Zelda games did. Remove the splotch of orange in the heart sprites too, red & black look much cleaner.

On a side note, is it normal for the sprites to become corrupt? Second dungeon in, and half of Link started to look garbled, the Keese were replaced by the old lady, and the the moving spiked traps became aliens. I used a clean ROM if memory serves.