How to add a Translation Patch to a Game ROM

To add community translations to a retro ROM, download a patch file, find a patch tool and use it to add a patch to the Retro ROM. Details here.

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Release] Gurren Lagann English Patch

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Bulk Slash English Fan Translation / Twin Sticks Patch Released

How to add a Translation Patch to a Game ROM

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Full(?) english patch for Summer Memories switch game was released