Great design but lacking depth...
Solid controls, nice visuals and for what it is its very well presented. The main problem I had with it was the repetition of it, now I understand its a supposed to be a arcade style game (hence the aim to obtain as higher score as possible) however there is one thing you could do to really improve it, and that would be by making it a side scroller. With a simple objective like trying to reach the end of a stage could make this game so much more enjoyable, and creating different looking and a more complex stages as you progress is a must.
Hope that helps for any ideas of future installments you may consider.