The game is pretty cool, I really enjoyed. Jobalidade has a slightly cloying, but over the game she gets a little bearable. After a few things are quite tedious time such as the crystals. Having to be picking up as many crystals is really boring, I mean, of course I need more bullets and missiles, and it requires me many crystals, but have to keep picking up several more to buy (especially for minigun), is pretty boring after a while.
Other than that, I must congratulate you for the graphics (I am a great lover of pixel art), and still more by sondtrack (if you have not been to the author, you know well how to choose them). The sound effects are also good.
Anyway, great job.