Sonic the Fighters was an arcade game which is also included in Sonic Gems Collection. There are 8 fighters playable in the game. Knuckles, Amy, Bark, Espio, Tails, Fang, Bean, & Sonic. After winning against all 8 characters, you fight against Metal Sonic. After defeating Metal Sonic, you will only have 15 seconds to defeat Eggman with no continues.