Here is the full list of all 24 Cube Racer achievements.
Find a yoffo cube in the campaign
Win 3 Sapphire Medals
Use your horn at least 30 times in one round
Receive a start boost for fast reaction
Exceed 80 km/h
Talk to a cube in the campaign
Exceed 230 km/h
Complete an online round with at least 6 players
Lose an online battle within 0,2s
Win 30 online rounds
Win 100 online rounds
Finish without dying, while all other players die somewhen
Unlock all obstacles on the lowest evolution
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
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
Place more obstacles in one round than all other players together