A liked a lot the music of the game! It's catchy, and it fits very well with the game style!!
The gameplay idea is very nice. It's addictive to avoid enemies, and then buy new items that will help you in the next try.
The controls are nice and very responsive!
The graphics are OK. I liked a lot the simplicity of it.
I just think that the background is disputing attention with the player, making it hard to see the player and enemies while moving. A thing that helps in these situations is making the background color less saturated.
Congratulations for the entry, the game idea is very cool and addictive!!