Here is the full list of all 45 Crimson Earth achievements.
500k zombies killed
50 zombies killed by light weapon
50 zombies disintegrated
100 zombies disintegrated
1000 zombies burned
1000 zombies killed by 12.7 machine gun
50 zombies burned
100 zombies burned
500 zombies burned
500 zombie heads were blown up
5000 zombies were blown up
500 zombies killed by 12.7 machine gun
50 zombies killed by 12.7 machine gun
100 zombies killed by 12.7 machine gun
500 zombies killed
1000 zombies were blown up
500 zombies were milled
50 zombies were milled
100 zombies were milled
500 zombies killed by automatic weapon
500 zombies were blown up
100 zombies killed by automatic weapon
100 zombies were blown up
50 zombies killed
100 zombies killed
50 zombies killed by automatic weapon
50 zombies were blown up
50 zombie heads were blown up
100 zombie heads were blown up
10 airstrikes
30 airstrikes
100 airstrikes
1000 zombies killed by automatic weapon
100 zombies killed by light weapon
500 zombies killed by light weapon
1000 zombies killed by light weapon
500 zombies disintegrated
1000 zombies disintegrated
1000 zombies were milled
1000 zombie heads were blown up
Zombies were redeemed 10 times
Zombies were redeemed 50 times
Zombies were redeemed 100 times
5k zombies disintegrated