If you own the game on Steam, you can find the file in your local installation directory:
Enjoy Sonic 3 & Knuckles with the enhanced gameplay and zones from both games. sonic knuckles wsonic3bin file install
It is a binary file containing the "locked-on" version of Sonic 3 and Sonic & Knuckles . When you "lock-on" the physical Sonic 3 cartridge onto the Sonic & Knuckles cartridge, it creates a single, larger game; this .bin file is the digital equivalent of that combined hardware state. Usage in Sonic 3 A.I.R. If you own the game on Steam, you