Add a homing missile to the player’s arsenal

The next requirement is for the player to have homing missile as a weapon. However, the missile should attack the closest enemy. Unlike when the enemy fires a homing missile, there’s only one target which is the player. This means that we need to loop through all existing enemies:

Then try follow the enemy. Notice that if the enemy died before the missile got to it or if it couldn’t find any target that it will just move up. But then check if there’s another enemy it can lock on to.

Now, the Player is armed with homing missiles.