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