I lost count of how many coins I put in Shoot-em-up arcade machines. It surely is not about getting the highest score. Trying out all the different weapons and seeing your weapons getting more and more powerful, destroying that big boss with ease is very satisfying.
In Unity, you can prototype your weapons very easily with basic 3D objects like Cube, Sphere, Capsule, etc.
In the Game window in the Unity editor, you can visualize the true power and mechanism of your weapons. Weapons too powerful/weak, as well as Too easy/hard powering up, can destroy an otherwise successful game.
Now no Shoot-em-up can be considered complete without special weapon:
My Super Shield bomb will protect me for 5 seconds, no enemy attack can get through !
As you can see, designing and implementing shooter weapons is a lot of fun, but it takes effort to get the balance right.
