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