I really liked playing it! The art, music and story are great. I love the snowman on the house. You have a really good interpretation of the theme.
In addition to invisible walls, you could have trees, rocks, something that tells the player where the map’s border is. It would clearly define the play area. And I like the snow on the character’s shoes when walking, wishing they would leave footsteps in the snow as well.
Great submission, good job!