This act introduces the Green Hover Wisp. When activated, Sonic can float for a short period and pass through certain transparent barriers. This Wisp is crucial for reaching distant platforms and bypassing obstacles. One Red Star Ring might be behind a transparent wall that only the Green Hover can pass through. Another could be on a platform far across a gap, requiring a precise Hover. You'll also encounter sections that combine Pink Spikes and Green Hover, requiring quick Wisp switching. Practice using both Wisps in conjunction to maximize your exploration and find all collectibles.
