The 25 Years of Sonic the Hedgehog

Sonic Adventure/International (1998-1999)

Sonic Adventure is the first game that Sonic and the other characters change their forms. Sonic Adventure was first made in 1998, and sold out in some countries. But in 1999, Sonic Adventure International was sold out to the rest of the world.

In Sonic Adventure, six characters spread out and complete their missions. The characters are Sonic, Tails, Knuckles, Amy, Big, and E-102 Gamma.

Sonic's mission is to defeat Dr. Robotnik from collecting the chaos emeralds.

Tails' mission is to collect all the chaos emeralds, help Sonic, and defeat Dr. Robotnik.

Knuckles' mission is to find all the Master Emerald shards, put them back together, and make Angel Island float again.

Amy's mission is to help a little bird find its brother and sister, and get away from the robot, Zero.

Big's mission is to find and fish out Froggy.

And E-102 Gamma's mission, is to help Dr. Robotnik, and then later help the little bird find his brother and sister. He gets destroyed after he completes his mission.

They also meet an echidna named Tikal, and see glimpses of time that happened 4,000 years ago in Mystic Ruin. They later defeat the evil Chaos from destroying Station Square. When Chaos collected all the chaos emeralds, he transformed into Perfect Chaos. But they didn't stop there. Chaos had only used the negative power of the emeralds. Sonic then used the positive power of the chaos emeralds, and transformed into Super Sonic. He then later defeats Chaos, and then Chaos, the chaos, and Tikal, all go back to their usual time.