: This version runs on RSDKv5U (Ultimate), a modified version of the engine that powered Sonic Mania .

A common fear with remasters is the temptation to "fix" what isn't broken. The RSDK version of Sonic 3 demonstrates remarkable restraint. The essential mechanics—the Insta-Shield (from Sonic 3 alone) and the elemental shields—remain untouched. However, the remaster introduces subtle, player-friendly features that modern audiences expect without compromising difficulty. These include:

. For years, fans dreamed of a definitive, modern way to play the combined experience. That dream largely materialized through the Retro Engine, also known as RSDK (Retro Software Development Kit).