(MD) Sonic the Hedgehog 3

The 3rd chapter in the blue hedgehog saga was released by SEGA in 1994.
Faster and graphically improved from the previous episodes, Sonic 3 features a new character, Knuckles, and adds the ability for Tails to fly for a short time and can swim underwater; there are 6 zones each one divided in 2 acts and levels are triple in the size compared to those in Sonic 2, through the levels can be found 2 different bonus stages : the first after collecting 50 rings and passing a checkpoint, the other is triggered by entering giant rings found in secrete passages.