It is important to clarify a technical distinction before providing an analysis of this topic.
(it was a Nintendo DS game), several high-quality GBA "demakes" recreate its story and features using the Pokémon Emerald pokemon heart gold gba rom
These demakes are legal gray areas (fan projects), but for the player seeking the feeling of playing HeartGold on a GBA emulator, these are the real answer. It is important to clarify a technical distinction