While plenty of new titles have been born of the iOS ecosystem - notably the likes of Angry Birds, Cut The Rope and Tiny Wings, there's still plenty of space in our hearts for those older, nostalgic classics. Sonic the Hedgehog is an absolute classic, particularly to those who used to love collecting those golden rings on their Sega Game Gear, and with a few titles featuring Sonic and Tails already gracing iPhones, iPads and iPod touches worldwide, the second episode to Sonic The Hedgehog 4 has just been released by Sega America.