Here is the full list of all 14 Transformice achievements. It takes around 200 hours to unlock all of the achievements on Windows.
Get 1000 cheese
Save 100 mice as a Shaman
Buy 2 hats in the shop
Buy 10 hats in the shop
Bring back the cheese first once
Bring back the cheese first 10 times
Get 1 cheese
Get 300 cheese
Get 9001 cheese
Save 2000 mice as a Shaman
Save 10 000 mice as a Shaman
Buy 20 hats in the shop
Bring back the cheese first 100 times
Bring back the cheese first 500 times