Here is the full list of all 14 Worms Clan Wars achievements.
Complete "Meat In The Middle"
Create your own clan, complete with emblem
Kill a total of 10 enemy worms
Fully customise your worms
Complete "The Mission Before Time"
Complete "Worm On Trap"
Complete "The Class Act"
Complete "Fugu Fountain"
Defeat the evil Lord Mesmer
Complete all Worm Ops missions
Kill a total of 100 enemy worms
Kill a total of 300 enemy worms
Win a ranked Clan Match
Complete a multiplayer match using your personally created landscape