3 at best.
I agree with AoShun, the controls do need work. It's practically impossible to attack the boats (if it's meant to be impossible, I retract that statement), and even though I "killed" three or more men (??) my score at the top was still 25 from killing the first one. The enemy count was still at 12, as well.
However, the extra two stars that kept this from being a 1-star rating are for the Ecco the Dolphin background music. Well done on nice music choice, not so much on the game itself.
-Blaze