It's Sonic 2, just slightly better with a hidden level cut from the original. Sonic 2, with Sonic CD, are amongst the best sonic games ever made. The only downside is the mobile controls. That's not the games fault however and if you have the opportunity to play this game on a console please do. It's amazing to think this game is pretty old now being released in 1992, yet, it's still so much better to play than most new games released today.