Here is the full list of all 14 Worms Clan Wars achievements.
Complete "The Mission Before Time"
Complete "Meat In The Middle"
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 10 enemy worms
Kill a total of 100 enemy worms
Kill a total of 300 enemy worms
Create your own clan, complete with emblem
Win a ranked Clan Match
Fully customise your worms
Complete a multiplayer match using your personally created landscape