Here is the full list of all 33 Zombie Vikings achievements.
Finish the story!
Spend a total of 30.000 gold in the store
Unlock all weapons
Defeat the Common Cold without hitting him with your sword
Complete all sidequests in the game
Complete the gnome cave without ever being detected
Hit a frozen enemy into 5 other enemies
Strike a frozen enemies back and forth 10 times
Have Beaknose defeat 10 enemies
Win against the Butterflies in Söcker without letting the other team score once
Clear the Tavern Brawl in Richside unscathed
Complete the secret Fe dream sequence
Have the crushers defeat 10 enemies
Open 25 chests
Have 6 enemies stunned at the same time
Kill 3 heavy enemies at the same time
Defeat an enemy by throwing a friend's head into them
Kill an enemy by throwing a chicken at them
Win a duel to the undeath
Kill an enemy with their own projectile
Keep an enemy airborne for 4 seconds
Catch the same enemy three times without them touching the ground
Have all players hold an enemy before it touches the ground
Make an enemy bounce on 4 others
Revive a friend by throwing both parts into each other mid-air
Get revived 50 times
Defeat a boss with zombie vomit
Perform the 4 player charge attack on the stitch zombie
Find the super secret developer area
Form a zombie tower of 5 with a guest of your choice
Escape the fishturd cannon unschathed with 4 players
Finish the Berzerker Factory without one player touching a conveyor belt
Unlock all runes