Really went in blindly, so I got surprise when I notice that the tower was attacking me. Going for collateral damage in this theme is a good way to respect it. I don't think I have any serious criticism outside that you played it relatively safe, but yeah you circumvent the problem with the health collectible. Although, I would of like something a bit more dynamic to protect myself from the bullet, like a temporary shield.
Overall everything was polish, no bug to report on the HTML5 version, art was looking good and the music fit. Good job !