Without a patch, the game lacks a speed limiter in windowed mode. Set your monitor refresh rate to 60Hz or use the "EnableFrameDrop" setting in the game's .ini file to play at the correct speed. Gameplay & Controls
Copy the GAME folder from your downloaded files to your computer. Run the launcher.
The collection includes three main game modes plus a "Special Stage Mode" (Blue Sphere). Sonic & Knuckles Collection
Since the game is considered "abandonware" by many, it is available through digital preservation sites, though the most stable way to play it on modern systems is using community patches.
The original 1997 requirements were very low, but modern PCs actually run the game too fast without patches.
You can find the game files or the original demo on preservation sites like the Internet Archive or Sonic Retro .