We once again see the main villain back in action with Dr. Ivo Robotnik making a second appearance. He has not changed any of his evil ways nor has he decided to come up with a new plan. In Sonic the Hedgehog, he wanted world domination via the Chaos Emeralds. Can you hazard a guess as to what his new plan is? Yep. You guessed it. World domination via the Chaos Emeralds. Hey you have to give the guy props for effort I suppose.
Sonic 2 has a total of 11 zones and they are, in order: Emerald Hill Zone, Chemical Plant Zone, Aquatic Ruin Zone, Casino Night Zone, Hill Top Zone, Mystic Cave Zone, Oil Ocean Zone, Metropolis Zone, Sky Chase Zone, Wing Fortress Zone, and of course the Death Egg Zone.
One of the best parts about Sonic 2 is having Tails as your buddy. I feel like every hero needs a sidekick and Tails delivers. Mario has Luigi, Batman has Robin, and now Sonic gets Tails. Somehow the universe seems like a better place now.