Here is the full list of all 38 Sonic Superstars achievements.
Defeated the true boss.
Cleared Trip's story.
Defeated 1,000 enemies.
Used Trip's double jump to defeat 100 enemies.
Collected 10,000 Rings.
Used Knuckles' glide to defeat 100 enemies.
Defeated the gold enemies in all Stages.
Used Tails' aerial attack to defeat 100 enemies.
Collected 100 Medals from Bonus Stages.
Used Sonic's Drop Dash to defeat 100 enemies.
Cleared Zap Scrap in Frozen Base without taking damage.
Used Amy's Hammer to defeat 100 enemies.
Collected 600 or more Rings from ACT "Fruit".
Turned Lagoon City's Goal Plate into a pile of fruit.
Cleared all of EGG FORTRESS.
Cleared all of FROZEN BASE.
Cleared all of CYBER STATION.
Cleared all of GOLDEN CAPITAL.
Collected 200 or more Rings when clearing a Stage.
Cleared all of PRESS FACTORY.
Turned super using the 7 Chaos Emeralds.
Used the White Emerald power "Extra".
Used the Yellow Emerald power "Slow".
Cleared all of SAND SANCTUARY.
Used the Green Emerald power "Ivy".
Cleared all of LAGOON CITY.
Used the Goal Plate to reveal the hidden Item Box.
Used the Light Blue Emerald power "Water".
Cleared all of PINBALL CARNIVAL.
Cleared an ACT "Fruit".
Cleared all of SKY TEMPLE.
Cleared 1 Bonus Stage.
Used the Purple Emerald power "Vision".
Cleared all of SPEED JUNGLE.
Used the Red Emerald power "Bullet".
Cleared all of BRIDGE ISLAND.
Cleared a Stage with a friend.
Used the Blue Emerald power "Avatar".