At this stage I have a more complete game however there are a few issues. I do now have prefabs of my different enemy sprites though I have an issue with the respawning of these different enemies I need to fix. These different enemies each have different variables for the speed and their health, which directly translates to how many shots they can take before they disappear. This is to represent the tougher tanks throughout history.
My hardest enemies characteristics 
A weaker enemies characteristics
My player script, with health points added in.
I added a bullet behaviour script here, which was needed to make the game calculate the health points of enemies and subtract one from the enemy each time the bullet object collided with the enemy sprite. I imagine it is in this script I will need to tell unity to delete bullets after a second or two so as not to clog the game up later with missed shots.
My first iteration of my bullet script
Also I added a score script, which displays in the top left hand side to the screen. This is a very simple score which just increases by one with each enemy destroyed. Thus giving the player an object to the game.
I used the below video to show me how to add my score count. What I like most about this method is how I can change how many points I want to give for the different enemies.
My First Iteration of my Score Script
There are a few things I need to fix and add in order to get the game to a state where you can reasonably say it is complete. I need to have the enemy destroy the player on contact with them, and have the player be able to restart the game once defeated with the push of a button (With a prompt that needs to appear on screen).
Also as of right now I have a strange issue where the enemy respawns but then acts as if there is no script attached to it. This will need to be fixed. Finally I would like to add some sound effects if possible to add polish and make the game feel more finished when playing.