I played your game and had fun. It took me a second to get what was going on though. (Skip to 6:38)
Yeah the towers aim a head of enemies to account for the time it takes for the bullet to reach them, but this fails if the enemies are about to change direction. I also don't know what you did to my game, but something clearly broke as all levels were unlocked eventhough you had barely completed any of them. Thanks for the video though ;-).