These images are screenshots from a Sonic 1 Forever mod that changes Sonic's sprites. It was canceled for a few reasons: -Lack of skill to animate sprites, some sprites looked strange using the RSDK Animation Editor -Lack of sprites made by the creator, unfortunately the creator didn't make many sprites (I didn't make these sprites), which makes it difficult to finish the mod -I was unable to request permission to use these sprites (The Sprites Resource website, where I found these sprites, crashed and I can't access it in my browser)
The Angie's Sonic mod has sprites similar to this one.
