The core of the update is the Plus Expansion Pack (also known as the Plus Content Pack). This DLC adds:

represents the definitive version of the classic blue blur's compilation, expanding on the original remaster collection with a wealth of new content, technical refinements, and fan-requested features. Released on June 23, 2023, the "Plus" update and DLC transform the experience for Nintendo Switch players by bridging the gap between 16-bit legends and the handheld era. The "Plus" Expansion Pack: Key Content

For the first time ever, Amy Rose is fully playable in all four main titles ( Sonic 1, 2, 3 & Knuckles, and Sonic CD ), complete with her signature Piko Piko Hammer.