A mushroom rock. great challange for experimenting with limited colors, really makes you think about the shading. had a hard time changing the outline to match the lighting so I just kept the same outline throught the piece.
I would love to know how to make this better (like a lot better  )
So please let me know | 
Weekly Challenge: Mushroom
That is pretty good, I like the concept and the way you try such limited colours.
I think that you can improve by using proper dithering in some areas e.g. cylinder and add some bright "lines"( idk how these light reflections are called) or cracks in order to shape the texture of a rock.
Also, the shading is quite strange, is the light source from above or in the upper right corner? If so, that upper left face should be dark instead of grey IMO.
Otherwise, that's very neat and cute I'd say