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