Here is the full list of all 31 Kill 'Em All achievements.
Kill 100 zombies overall
Kill the Furies
Kill 50 zombies with melee
Kill Panzer
Kill 40 zombies with headshots in campaign
Kill 50 zombies with grenade in campaign
Kill no zombies in a level in campaign
Kill 100 zombies with headshots on campaign
Kill 10 zombies with melee
Kill 80 zombies with headshots in campaign
Kill 60 zombies with headshots in campaign
Kill 10 zombies with grenade in campaign
Kill 20 zombies with grenade in campaign
Kill 20 zombies with headshots in campaign
Kill 100 zombies with grenade in campaign
Kill 200 zombies overall
Kill 500 zombies overall
Kill 1000 zombies overall
Kill 5000 zombies overall
Survive 5 Waves in arcade
Survive 10 waves
Survive 20 Waves
Survive 30 waves or more in Arcade
Kill Zomowser
Kill Cryo
Kill the final boss
Kill 100 zombies with melee
Find the secret level
Find the easter egg on 'Not all Peaches'
Launch all missiles in 'Kostly Affair'
Find all easter eggs in the game