Originally released for the Game Boy Advance in 2004, Pokémon FireRed and LeafGreen were the very first remakes of mainline series Pokémon games, specifically of the original Red and Green versions (Red and Blue here in the States). Given there was a nearly-decade-long difference between these releases, it goes without saying that a lot of standards in game design and hardware capabilities had changed, and while the original games were excellent as they were, it’d be a waste not to add at least a few changes and improvements.
from GameVerse