Pretty good prototype!
It's a bit short, but very polished. Would it be take too long to add a harder enemy, even if it's just a normal enemy with higher HP? I think the game suffers a bit from how easy it is.
I never figured out how to move the camera, does it say anything in the game itself? I could only find it in the comments.
I'd love to see a longer version of this. Now that you have the basic code laid down, it should theoretically be easier to add more content, right?
Good job!