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