Not a bad game, but you lost points.
But you need to use different gradient colors with the enemy shapes and the background. Use dark blue and light blue (or some other color) for the enemies. If you use black in the gradient and black for the background, you end up having hidden edges on the enemies. Several times, I ran into an enemy that wasn't there because the edge matched in with the background, but the computer still registered it as an enemy edge.
I also docked you points for the ads. There are too many. I understand one at the loading screen. But I got one when I checked the high scores before I even played. Then I got another after submitting my score, and every time I checked the scores. That's too many. After playing for several times, it's possible to have viewed 10 ads, and at 15 seconds each, that's 2 1/2 minutes of waiting. This was a problem with Countermeasures also, but I didn't review that one.
Ads help you out, but if you add too many, it hurts you because no one enjoys the game.