I set up a game controller which releases waves of zombies, making more zombies spawn per wave completed. Each round is complete once all of the zombies are eliminated by the player.
Each gun features a reload system. Each gun has a different reload time which is balanced as a counterweight to the fire rate. So a gun with a higher fire rate such as the Rifle takes longer to reload than the pistol.
I used the built-in Unity particle system to create effects such as sparks, water and fog. This was to add an apocalyptic feel to the game.
I created some power ups that can spawn when a zombie is killed. These include gliders, more ammo, coins. The coin system can be used to purchase upgrade the users gun by selecting one off a wall.
The user is able to buy their way into certain areas with their coins to extend the play space. Also, the user can access the minimap which displays their position realtime.