AI Fixed, Increased Difficulty

—I was thinking of having a health bar instead of lives. Could work
either way.
—We need to add in life power up and score power up. I imported the
heart prefab but it is hard to use. Coin prefab didn’t work.
—We need to finish: pause game interface, better gui (how to play). fix
some more AI (have AI respawn after certain amount of time), add a hud
system for collision detection