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