Space Defence

This is my first real big game that I feel comfortable sharing. Made with a really old version of GameMaker, it is a tower defense game (and I know I spelled "defense" wrong in the title; forgive my ignorant child self) that uses towers to defend against spaceships that, for some reason, follow a very specific path on the ground. This game was my first time creating a game using actual code. You should be able to beat it in 30-60 minutes. *Tip: Place your towers toward the bottom of the screen, trust me.