Here is the full list of all 42 Winter Dream achievements.
Reject Rin's offer.
Save Caron from his fate.
Learn the truth about Caron and their world.
Give up on life.
Don't make any friends during your vacation.
Get the worst ending for Rose.
Finish Rose's route with her as your girlfriend.
Finish Rose's route with her as your best friend.
Tell a story at the orphanage.
Put an a play at the orphanage.
Juggle at the orphanage.
Tell jokes at the orphanage.
Confess to Rose.
Agree to being best friends with Rose.
Help the young kid.
Lose your friendship with Rose by being a horrible person.
Don't help the young kid.
Hang out with Rose twice on the third day.
Finish Gwen's route with her as your girlfriend.
Confess to Gwen.
Finish Gwen's route with her as your best friend.
Let Gwen know that you're friends.
Get the worst ending for Gwen.
Get Gwen's neutral ending.
Get Gwen to despise you.
Don't respect Gwen's privacy.
Admit to being curious about Gwen.
Respect Gwen's privacy.
Say Gwen is cute.
Hang out with Gwen twice on the third day.
Finish Velda's route with her as your best friend.
Get the worst ending for Velda.
Finish Velda's route with her as your girlfriend.
Stay behind when Velda leaves to save Gwen.
Go with Velda to save Gwen.
Think about Velda when you're in trouble.
Tell Velda that you want to be friends.
End up with Velda leaving.
Confess to Velda.
Call Velda a bitch.
Promise to keep Velda's secret.
Hang out with Velda twice on the third day.