Here is the full list of all 10 Return to the Skyway achievements.
Throw an animal 100 times.
Throw an animal 50 times.
Outrun Bruno.
Complete the first level.
Pickup the final missing ship part.
Pickup the second missing ship part.
Throw an animal 10 times.
Pickup the first missing ship part.
Pick up Soos.
Pick up Chad.