I love the artwork so much! It's super cute. The parallaxing effect on the background works really well to convey motion! I think adding more detail to the skyscrapers closer to us would help emphasize the distance. I also love the dithering of the skyline.
The music is great too, it bops. I like how it adds and removes elements to stop from being too repetitive.
I do think the game starts off way too difficult. The balloon is very difficult to keep track of. It took me several tries to make it past the first two enemies, I think the difficulty should ramp up slower.
I really like it! Well done!