Sonic the Hedgehog 2 is getting a 3D Classics version which is scheduled to come out in Japan on July 22. 3D Sonic the Hedgehog adds a new Ring Keep mode where you start a stage with 10 rings, but each time you take damage the amount of rings that fly out is halved. The 3DS version supports two players through local wireless connectivity. Both players will need a copy of 3D Sonic the Hedgehog 2 to control Tails (and breeze through the game) or try the two player versus mode.
Like other 3D Classics, M2 added a quick save feature and an option to play the Japanese version or international release (the games are about the same, though).