A Blue remake? Hmm, I'm honestly wondering whether this should be in the Sideshow Showcase, since all you're really doing is changing the graphics in Fire Red. :\
Anyway, some of the tiles kinda clash. The houses in Pallet Town, for instance, look really out of place n contrast with the trees and mountains.
Sprites could use some work too. The back of Red's hair on the back sprite look pretty flat, and green/Blue...Idk there's just something about him that looks off.
Anyway, good luck.