Really quick and easy achievement that can be unlocked within seconds of starting the first level.
From the starting point, pick up the blue nitro jar to the left of Putty by auto absorbing. Move back to the right and you will see a green frog on the edge of the ledge. Position Putty behind the frog, one step up, and then simply press

while facing to the right to throw a bomb at the frog.
Once the bomb goes BOOM, achievement unlocked!