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