Simplify the following text for a Grade 5 native English-speaking person.
Original: The division of Action Stages and Adventure Fields was a serious departure from previous Sonic games . In addition , unlike the previous game in the series , Sonic Adventure has six different characters to choose from : Sonic , Tails , Knuckles , Amy , Big and E-102 Gamma ; each with their own style of gameplay .
Simplified: It was not as popular as Sonic Adventure .