DLC, as it includes significant difficulty adjustments and bug fixes for the new content. asia.sega.com Key Content Updates & DLC

The chaos began when ‘DumpsterFire_Direct’ revealed himself. He wasn’t a hacker. He was a former SEGA middleware engineer who had worked on the Hedgehog Engine 2. The “Update” was a retrieval algorithm. He claimed that when Sonic Team ported Frontiers to the Switch, they didn't delete the original, unstable “Phantom Ruins” prototype. They just compressed it, layered the retail game on top, and shipped it. The 47MB NSP was a key to decompress the forbidden layer. Sonic Frontiers Switch NSP UPDATE DLC

An alternate ending scenario called "Another Story" that replaces the final chapter New Playable Characters: DLC, as it includes significant difficulty adjustments and