Ancient Egyptian Tower Defence (also aliens)

Introduction

This is my second project and first game I've made using the Unity games engine so feed back and advice is very much appreciated, I hope you enjoy. 

Premises

As sad as it is to say there probably weren't any alien in ancient Egypt but that doesn't mean we can't have fun with the idea. You play as an alien who has crash landed in the middle of an ancient Egyptian city. The Egyptian have mistaken you for a god along with another alien who is also stranded on the planet. The other alien doesn't take kindly to the you taking attention away from them so they release hordes of ancient Egyptian monster augmented with alien technology to destroy you and the city you've crashed in. To defend your self you team up with the Egyptians to create defence tower or turrets which are built from a combination of your own and the Egyptian technology.