Martians can't count to three.
Not unlocked yetSave all the cows on all the 'Meet the Martians' bonus levels in Veteran difficulty.
Challenge Accepted... and Defeated!
Not unlocked yetSave all the cows throughout all the Challenges in Veteran difficulty.
"Beware Planet Earth!" Turbo Prime EX Plus Alpha
Not unlocked yetSave all the cows on every level of the Story mode in Veteran difficulty.
Spotless Winter
Not unlocked yetSave all the cows on every Story level of winter.
They're coming to get you, Barbra!
Not unlocked yetSave all the cows throughout the whole 'Zombies of Mars' Challenge category.
Chekhov's Raygun
Not unlocked yetSomeone's gotta fire it before the end.
When you have to shoot, shoot! Don't Talk!
Not unlocked yetUse the Zapper to finish a Martian.
Welcowme on board!
Not unlocked yetLaunch the game for the first time!
The Man With the Martian Gun
Not unlocked yetGet the Zapper.