Self-doubt: Opinion Needed

Being solo developer with only 2 short games in my portfolio.  The second game, TornaDuck is for BossFight game jam, which took 3 weeks to complete. I did everything myself from drawing to coding using Unity. Although the game is done but I feel the art makes it looks unprofessional. 

Can someone comment on the game, especially the art work? So I know what others thinks of my game?

Below are some screenshot of the game. 

Hope the game give you joy!

Kind regards

Panduck