Here is the full list of all 13 Alicemare achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Reach level 7 in NuTetris
Look the true end
Speak to Cliff on the phone
Find the Cheshire Cat ending
Find the extra scene
Choose Joshua
Choose Stella
Choose Chelsy
Choose Letty
Look under the Joshua's bed
Think of another answer to the river puzzle
Eat the poisonous mushrooms
Play Stella's piano