graphic style
As this game is a puzzle platformer, the graphic style must not get in the way of quick and efficient understanding of a level.
Therefore, I want to go for cel shading with outline and few textures.
However the player must feel encouraged to explore, therefore the world must look good and have enough decoration and variety to generate a sense of awe whenever the player reach a new level/biome.
The setting of the game is giant spaceship that has been crashed for hundreds of year on an foreign planet. The spaceship has been partially destroyed, and has been reclaimed by alien vegetation.
The combination of overgrown spaceship and cel shading should create a look similar to Hollow Knight's GreenPath biome :
