OK, I can appreciate the rotating ring defense with the ability to move vertically to get a more accurate shot on incoming projectiles, but I question the use of only a single protection ring for what is basically the most vulnerable section of the elevator. Even if they hadn't blown up most of the lasers with a special gun, and again I appreciate the thinking on the designer's part to allow diminished functionality after the loss of most laser units, the fact that the ring could be overwhelmed at all, diminished or not, means it was only a matter of time before some guy shot enough missiles at one time and from enough different directions to exceed the ring's ability to destroy them all.
Also, why wouldn't you just put rotatable lasers on the whole ring instead of slightly less than half? That would at least cover for my multi-directional mass fire scenario.
