The powerups aren't exactly intuitive. I know there are instructions, but in a game as simple as this, that's more of a crutch than anything else.
The ship's movement wasn't really responsive enough to push it into the region of experience I would call "fun."
Maybe it was just me, but the framerate was painfully low. I don't normally have framerate issues on Flash games, so I am wondering if the natural framerate is just low, or something. Whatever it was, it strained my eyes too much to play longer than a few minutes.
I gave it 2/5. It could be doing what it's trying to do a lot better.
It feels... restricted. As far as I can tell, it is perfectly unclear as to how money is being earned. It just hands it to you at the end of the level. Similarly, there is almost no indication as to whether you are hitting something, unless it dies. Having scrollwheel weapon change is bit odd, considering that most people will be playing tihs in a browser.
 "Hands of War"){kind=icon}
 "Feudalism II"){kind=icon}
 "Kingdom of The Wind"){kind=icon}
 "Zombies!"){kind=icon}
 "Ether War"){kind=icon}
 "Spaceship Escape 2"){kind=icon}
 "Skies over London"){kind=icon}
 "Epic war"){kind=icon}
 "Cirplosion"){kind=icon}
 "Paw Frenzy"){kind=icon}
 "Robot Jim!"){kind=icon}
 "Doublue Wires"){kind=icon}
 "Orbitrunner"){kind=icon}
 "Tech Wars"){kind=icon}