the name is Greeen the Hedgehog,but it is also known as sonic Xmas (hack)
download for free here: http://www.doperoms.com/roms/sega_genesis/Sonic+Xmas+%28Hack%29.zip/564984/Sonic%20Xmas%20.html
images?
http://www.vizzed.com/videogames/gen/screenshot/Sonic%20the%20Hedgehog%20-%20Christmas%20Edition-2.png
https://i.ytimg.com/vi/UVMdr7Zt0gY/hqdefault.jpg
I actually kinda like this, looks bootleg but in a weird cool kinda way and the colors are great!