yes it's using a script to check for the player left/right click (left is held down to fire the rapid fire gun and right mouse is clicked to launch a torpedo)
only 1 bullet (from each gun) can be fired at a time so the rapid fire gun needs to be a little slow to allow for it to actually travel a good distance and still move reasonably to allow any objects to be "detected" (*on that note, actual hits are detected by distance so this wouldnt work well when targeting large objects*), all shots fire in a straight line from their original rotation so turning the ship etc wont effect the bullet - skill shots for moving targets only
and a script on each bullet (same script but with an array setup for the different settings) to control them.
ideally you would include a script on the enemy ships to mark them as such to make the bullet "hit" detection better as right now it just checks everything.
(also you would need some script for enemy AI)
currently the script is unlimited ammo (just reloads as soon as the bullet has travelled it's maximum distance) but with a little extra tweaking you can certainly have an ammo count and even different guns (maybe a homing missile or an emp torpedo)