Gamma Emerald is not a GBA ROM
What you actually download
The creator distributes a Windows ZIP through the official itch.io page. After extraction, you run the included Windows executable. The game's HD-2D presentation, real-time lighting, shader compilation, desktop GPU requirement and multi-gigabyte install are all separate from the original Game Boy Advance cartridge format.
Why search results can be confusing:
- the project remakes the story and locations of Pokémon Emerald;
- many unrelated Emerald fan projects are ROM hacks;
- third-party sites sometimes label any fan remake as a GBA hack;
- mGBA appears in related searches even though the official page never lists it.