Game Boy Emulator for iPhone & iPad | Retropa

Start with a .gb file

Everything starts with a game file you already own. Retropa does not ship games or BIOS files, so have the .gb ready before you open the app and keep an untouched copy somewhere outside it.

• A .gb file is a Game Boy game; .gbc means Game Boy Color.
• Renaming an extension does not turn a game into a different system.
• Hold on to the original archive until the game runs properly.

Which core runs Game Boy games

Retropa ships four cores that can start a Game Boy title, and the choice is yours per game. mGBA and SkyEmu cover GB, GBC and GBA; SameBoy concentrates on GB and GBC; JGenesis handles GB next to its Sega systems. mGBA is the default, so most people never need to touch it. If one core stumbles on a title, try another before blaming the file.

• mGBA is the default and a safe daily pick.
• SameBoy is built around GB and GBC accuracy.
• Your core choice sticks per game.

Import the game from Files

In a list, a cloud placeholder is indistinguishable from a real file, yet the import fails until the bytes are actually local. Pick the file from the import entry in the Retropa library, then open it. Confirm picture, sound and the default on-screen controls before you start customizing anything.

Choose a layout that fits the original screen

Game Boy games want a directional pad, A and B, and Start and Select. In portrait the screen sits above the controls, which works for one-handed play; landscape gives your thumbs more room. Whichever way you hold the device, make sure the skin leaves the game view clear and all six inputs are easy to reach.

• Test each button, not just how the skin looks.
• Delta .deltaskin packages import fine, but a DS or GBA skin is not a GB layout.
• Premium skins and advanced filters sit behind Retropa Plus.

Green screen, LCD grid or clean pixels

Start from the untouched picture, so you have something honest to compare against. A DMG preset recalls the four-tone reflective LCD of the original handheld; an LCD Grid lays a subpixel structure over it; a CRT treatment takes the image somewhere else entirely. Retropa's advanced filters work from the real output area instead of demanding an integer scale factor, so proportions hold on any iPhone or iPad.

• A filter changes how the picture looks, not the game's resolution.
• No filter will rescue a file the core cannot run.
• Compare with the original picture before you keep a preset.

When a Game Boy import or save fails

Before changing anything else, note the extension, the system you selected and the exact error text. If Files is still fetching the original, let that finish, then import again. A game's own save data is not the same as an emulator save state; never rename one into the other, and back up before you move a save between cores or apps.

• Note the app version, system, core and error text for support.
• Never attach commercial ROM or BIOS files to a support request.
• Return to the default skin and a plain filter while you isolate a problem.