The enemy I had in the game would spawn and go down until it left the screen. I updated the enemy script to allow two new types of enemy movement. Now when the enemy spawns in addition to going down can now spawn going left or right.
I did this by getting a random number and using a switch statement to determine which movement type will spawn.
I also created a more balanced spawn system for the power ups.
Now things like health and special ammo types will spawn much less frequently than things like ammo or speed power ups.
This has reduced the amount of clutter on the screen by reducing the amount over power ups that will spawn together.