Word for an inaccurate work by an artist, who ineptly misrepresented their subject?

Solution 1:

The word you are looking for is knockoff (or knock-off) — (M-W)

a cheap or inferior copy of something

a copy that sells for less than the original; broadly : a copy or imitation of someone or something popular

"That purse is a knockoff. "

This question has evolved to be a request about a shoddy representation. For that, one might use the term hack (job) — (UD)

something done shoddily or ineptly

"The script was such a hack job that they had to bring in a new writer to completely rewrite it."

Solution 2:

From your description I think you're looking for caricature:

a picture, description, etc., ludicrously exaggerating the peculiarities or defects of persons or things.

(Dictionary.com)

Solution 3:

The German word ersatz (pronounced ['ʔeəzats] 'air zotz') is often used with precisely this meaning.

Solution 4:

Try simulacrum defined by Oxford Dictionaries as

An unsatisfactory imitation or substitute.

Also, you can use ersatz defined by Merriam-Webster as

Being a usually artificial and inferior substitute or imitation.

Solution 5:

"a fake" and "a sham" come to mind.

fake - (noun) - One that is not authentic or genuine; a sham. TFD

e.g.

"That blood on the floor was clearly fake." (adj)

"He was wearing a fake mustache." (adj)

"It was a sham diamond." (adj)

"Their marriage was a sham."

However, if the reproduction looks so much distorted, I'd call it "a rough imitation"

Then again, if those distortions were intentional, I'd agree with Josh's answer that the author created a caricature.