The most reliable way to play the game with all features, including the (which adds Mighty and Ray), is through official digital stores: Nintendo Switch : Runs at a smooth 60FPS with HD graphics.
Sonic Mania is available on multiple platforms, including:
This official GameCube disc plays perfectly on backward-compatible Wii consoles and contains almost every classic 2D Sonic title.
Even if you stumble across a site offering a .wbfs or .iso file labeled “Sonic Mania Wii,” it’s almost certainly one of three things: