Here is the full list of all 43 Save the Dodos achievements.
Kill 20 dodos
Save 50 dodos
Move 5 tiles in less than 5s
Clear a level in less than 25s
Clear a level in less than 20s
Clear a level in less than 15s
Reach 1500000 points overall
Kill 50 dodos
Move 10 tiles in less than 5s
Move 15 tiles in less than 5s
Complete 10 achievements
Complete 20 achievements
Complete 35 achievements
Win 50 stars
Lose a dodo next to an exit
Do nothing during more than 30s
Do nothing during more than 60s
Clear 25 levels
Save 5 dodos at the same time
Kill 5 dodos at the same time
Get more than 1 special dodos
Lose in less than 20s
Lose a dodo in less than 1s
Play a level more than 5 times
Accelerate time more than 25s
Keep a tile pressed more than 25s
Save a dodo narrowly
Reach 500000 points overall
Reach 10 defeats
Clear 100 levels
Kill 100 dodos
Save 100 dodos
Save 200 dodos
Reach 25 defeats
Reach 50 defeats
Clear 60 levels
Win 150 stars
Win 300 stars
Get more than 2 special dodos
Get more than 3 special dodos
Play a level more than 10 times
Play a level more than 25 times
Reach 1000000 points overall