Good start and solid level design. I liked the many possibilities to take cover. For my personal liking, the game feels a little too mindless. Right now, there's no reason to ever not shoot. Considering the name is "Counter Invasion" now, one simple way to make that decision more interesting might be to add civilians to levels that make you lose health when you shoot them. If you want to go more for the mindless shooting experience, I'd prfer an auto-shoot button to manually mashing your mouse.