Here is the full list of all 33 Beware Planet Earth achievements.
Save all the cows throughout all the Challenges.
Save all the cows throughout the whole 'Back to Basics' Challenge category.
Save all the cows throughout the whole 'Ninjas in the Snow' Challenge category.
Save all the cows throughout the whole 'Maid Raid' Challenge category.
Save all the cows throughout the whole 'Zombies of Mars' Challenge category.
Survive all five 'Meet the Martians' bonus levels!
Save all the cows on all the 'Meet the Martians' bonus levels.
Save all the cows throughout the whole 'Hard Rock from the Red Planet' Challenge category.
Survive all five 'This is Halloween!' bonus levels!
Save all the cows on all the 'This is Halloween!' bonus levels.
Save all the cows throughout the whole 'Weird Science' Challenge category.
Save all the cows on every level of the Story mode.
Save all the cows on every Story level of winter.
Repel the Martian threat for good!
Someone's gotta fire it before the end.
Defeat a Winter Story level without letting one Cog disappear.
Survive fall!
Save all the cows on every Story level of fall.
Behold a Cow going through a quantum wormhole!
Witness or cause the collapse of a quantum wormhole.
Successfully start a chain reaction using 4 or more Explosive Barrels!
Save all the cows on every Story level of summer.
Survive summer!
Blast at least 8 Martians with one Bomb!
Survive spring!
Save all the cows on every Story level of spring.
Use the Zapper to finish a Martian.
Get the Zapper.
Launch the game for the first time!
Save all the cows on every level of the Story mode in Veteran difficulty.
Save all the cows throughout all the Challenges in Veteran difficulty.
Save all the cows on all the 'This is Halloween!' bonus levels in Veteran difficulty.
Save all the cows on all the 'Meet the Martians' bonus levels in Veteran difficulty.