Here is the full list of all 12 Christmas Defence achievements.
Drive away the bad beasts.
Hedgehog takes a position.
Hedgehog attacks at least 3 animals.
Go through the level of not more than 60 seconds.
Complete the level using only dogs.
Complete the level using only squirrels.
Complete the level without using dogs.
Go through 3 levels.
Go through 9 levels.
Scare at least 10 bad animals with a petard.
Accumulate 20 buttons.
Go through 12 levels.