Looking for a game title

So this game is pretty old, basically you are controlling a spacecraft and you are shooting anything that moves on the screen.
By doing that you earn some sort of money, with which you can upgrade your ship.
There's very little that I remember of the gameplay, but I do remember that one of the last bosses(if not the last) looks like a human face, where there's two eyes, one nose and one mouth freely flying around and shooting.

Anyone know this game?
Please let me know :)