Here is the full list of all 12 Mervin and the Wicked Station achievements.
Get 50 extra lives
Get 25 extra lives
Get 10 extra lives
Complete all the levels
Freeze 100 monsters
Freeze a star-villain
Freeze 50 monsters
Freeze 25 monsters
Freeze a balleye
Get rid of a banana-leg
Complete the tutorial
Launch the game between 12 and 18 April