It's not bad. Although one thing that I often point out is when drawing something where you only draw the lineart and nothing else (no coloring, no shading), it's important to have a variety of thickness throughout the drawing (thin to thick, medium, thick to thin, thick to medium, etc), and also using various gradiants (light to dark, dark to light). If you do that well, then even though it's lineart, you can tell a person who sees it where the light source is, and help the image to look rounder/pop out more.
(Yes, I was bored/not wanting to write my essays...)
Obviously, the one on the left is drawn in one single shade of darkness and the same thickness of line whereas the one on the right has line variation and a little bit of gradiance. Also, it doesn't hurt to add minor details like adding texture to something, such as very lightly drawn scales in your case.
Oh and yes, that's a zombie mushroom on the right. O.o
