Complex sentence: Sonic's main means of attack is the Spin Attack, where Sonic curls into a ball, which can be performed by jumping in the air or by pressing down on the D-Pad while moving on the ground.
Split into simpler sentences: Sonic's main means of attack is the Spin Attack, where Sonic curls into a ball. This can be performed by jumping in the air or by pressing down on the D-Pad while moving on the ground.