I feel like the truck is at a weird angle. maybe rotate it up more? also, that grey line around the crab's outline is not too attractive right now, but maybe with color or shading it will be better.
I like the style but i found it hard to notice the eyes on the crab. they were more noticable on the outline drawing. try working with tones and shades?
any suggestions for color or texture
i'd also like an opinion and ideas for the background or if I should even have one
i was thinking maybe a skyline silhouette with crumbling buildings and overgrowth