As from the pictures, you can see that this is a hack of the SMB game. It just has changes in most of the sprites. All music and sound FX are the same. This hack is very easy to do because the SMB game engine is so basic. There are some websites that tell you how to hack into the game engine and change things around. This person was'nt able to change the whole game completely, but its a sonic hack so it has to be here. Soon, I will have info on how to hack into a newer NES mario game (like SMB3) and turn it into a phat sonic Hack. So GET Ready!!!