I wanted to test your game, but my computer at work can't run the game. However I wouldn't worry. The computer hasn't been designed to run games and I'm even in doubt wheter Directx9 is installed on it or not.
I'll just have to test it when I get home.

On the other hand, I tried a small game yesterday which totally reminded me of your game. It's called Soup Toys. You can build towers with it and shoot down with cannons afterwards + much much more. Perhaps you can get some inspiration from it