Here is the full list of all 29 Worms W.M.D achievements.
Reach Sheep Rank
Complete 5 Challenges
Complete 15 Campaign Missions
Complete 40 Sub Goals
Kill 500 worms
Craft every weapon in the game
Craft 30 weapons across all game modes
Fully customise a team of worms
Get 80 kills in a Tank
Collect a wanted poster
Complete all Training levels
Gain a Gold Medal on all Training levels
Complete all the Basic Training levels
Complete Navigation Training
Get 80 kills in a Mech
Play 50 Online Multiplayer Games
Get 80 kills in a Helicopter
Win an Online game with all worms in Buildings
Get 40 kills using a Mounted Gun
Finish a game with a worm on more health than it started with
Kill 20 worms with Prod
Win an online multiplayer match in Sudden Death
Kill 4 worms in a single turn
Win 3 online games in a row
Play a Ranked Match
Complete the Campaign
Complete all Challenges
Complete all the Sub Goals
Unlock all the Customisation Items