Here is the full list of all 24 Cube Racer achievements.
Use your horn at least 30 times in one round
Lose an online battle within 0,2s
Talk to a cube in the campaign
Exceed 80 km/h
Exceed 230 km/h
Complete an online round with at least 6 players
Win 30 online rounds
Win 100 online rounds
Finish without dying, while all other players die somewhen
Unlock all obstacles on the lowest evolution
Win 3 Sapphire Medals
Blow up 7 obstacles with one explosion
Freeze a player within 3 meters of the finish
Win 5 consecutive online multiplayer rounds
Win 10 consecutive online multiplayer rounds
Overtake a frozen player
Receive a start boost for fast reaction
Unlock all obstacles, including all evolutions
Earn a total amount of 20,000 cash
Win an online race with at least 4 players
Unlock all achievements
Kill every other player in one round
Find a yoffo cube in the campaign
Place more obstacles in one round than all other players together