Here is the full list of all 20 Slowdrive achievements.
Get all ice wheels
Get 3 stars on 60 levels
Get all gold wheels
Find 60 leaves
Complete all levels
Find 30 leaves
Drive 100km
Find 15 leaves
Finish the game
Drive on two wheels 15 meters
Get 3 stars on 30 levels
Get 30 gold wheels
Jump 40 meters
Get 3 stars on 15 levels
Get 15 gold wheels
Drive 10km
Jump 20 meters
Faster than 3 stars for 1 second
Achieve speed 50kmh
Get 3 stars on any level