Here is the full list of all 15 Roller Coaster Rampage achievements.
Achieve 16x Multiplier 16 Times
Receive a Gold Star
Complete 1 Coaster in Freeride
Perform a Barrel Roll
Complete a Loop
Complete 15 Corkscrews
Unlock All 30 Levels
Build 50 Loops
Collect 1000 Gems
Complete All 30 Levels
Complete 100 Outside Stunts
Destroy the Seamonster 8 Times
Link 250 Track Sections
Build 100 Complete Coasters
Receive Gold Stars For All 30 Levels