Here is the full list of all 20 Commander Cool 2 achievements.
Play story with 2 players
Beat level 15
Kill 100 enemies
Survive level 10
Collect 1000 coins
Kill the boss in level 5
Die 10 times
Kill 10 enemies
Start the first stone age Level
Complete all stone age levels
Complete all stone age missions
Collect all stone age diamonds
Kill 1000 enemies
Collect 100.000 coins
Die 1000 times
Collect 10.000 Coins
Die 100 times
Escape the T-Rex in level 20
Kill the boss in level 25
Kill the final stone age boss