Hey timbs85, I got it working! I liked it as well, taking down enemies was pretty quick which was satisfying. I like there was one clear objective (defend the launcher), but is there an end goal or just survive as long as possible?
So the basics are good, I think you can add extra powerups, different types of enemies, and switch up the objectives every once in a while. The foundations of a really good game are here.
Overall, I liked it, and I think you can expand it!