i really like that you managed to implement nice music and sounds in a week!! And I think Tower Defense Games are really nice and so is this!
But currently I think you make money a bit too quick. I could basically just spam whatever from Wave ~15 on. Also you could maybe add some indicator on which object your currently hovering when you upgrade something, because when I had many turrets of the same type standing next to each other it was kinda hard to tell which one I'm currently on.
The visuals are really nice and the Intro is also nice to have done in one Week!