Since this game have a theme of adventure/platformer, there will be areas that resembles of a forest.
Grass: It’s natural to have grass in the area to give the identity of a forest.
Dirt with a dead face in it: The dead face in the grass gives off a sense of danger and urgency in the adventure the player will be apart of.
Clouds: Supplement the background to give it a bit of life in the area.
House: Is the home of the player and can be serve as a relief of the player. It’s there as a saving point.