Here is the full list of all 24 My Little Worms achievements.
Buy a Transparent worm
Buy all worms
Buy a King worm
Buy a Detective worm
Buy a Rainbow worm
Buy a Snail worm
Buy a Dino worm
Buy a Pink worm
Buy a Wicked worm
Buy a Bird worm
Collect 100 coins
Buy a Cow worm
Buy a Goat worm
Buy a Farmer worm
Buy a Drunk worm
Collect 50 coins
Pass 15 obstacles without collision
Buy a Santa worm
Buy a Tattoo worm
Collect 25 coins
Buy a Green worm
Pass 10 obstacles without collision
Buy a Yellow worm
Pass 5 obstacles without collision