I managed to color to shade this and add a background. I had to redo the lines but that's fine. It's also a higher resolution now, I didn't realize it saved in a low resolution until I brought it back into Photoshop and saw particles around the original lines. I had to fix that too but that was simple, just used a blur tool to remove and blend it back in. I actually really like this though, I would do something different when it comes to shading. The lines are behind the shading, next time I will shade the lines desperately so it doesn't end up looking like it does here.

I know, the shading is different than Adventure Time but I wanted to make it my own in a way.

I am taking commissions on pictures like this, they will be $5 as a base price but if the character is really complex, it can go up to $10 PM me if you are interested.
Vocol (c) vocol

Note: I just realized he looks lost but I still like it.