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