Quake II/Big Gun

The objective of this level is to destroy the Big Gun and disable the Stroggos planetary defense system. You should arrive at this level well-armed and in good health. Pick up what you can in the first room upon arrival and quick-save the game. As soon as you pass through the first set of automatic sliding doors, they close behind you and lock, so there's no turning back.

In the second room with the blue crystal and vertical red laser beam you encounter a monster like none you've seen before. It looks like an ugly cybernetic hybrid of turbine helicopter, wasp and humanoid. A volley of explosions announces its emergence from a trap door at one end of the room. It hovers in the air, and attacks almost immediately with a hail of rockets and bullets. It's tough to kill, but you can do it with a sustained assault of rockets, rail gun slugs or HyperBlaster fire. If you have a Quad Damage and are otherwise short of ammo, now would be good time to use it. Try to use what little cover is available and stay out of its line of fire.

After the monster is destroyed, one door can be opened, opposite the one through which you entered the room. Also take note of the other door with the black and yellow diagonal stripes, still locked: It will be your escape route later. The rest of the opposition consists of guards armed with blasters and machine guns, and are easy to eliminate. Make your way to the extreme eastern end of the facility where you'll find just a couple of guards at the Defense Monitor screens.

Quick-save the game just before you trigger the self-destruct sequence, as the final run is difficult to accomplish, even if you know the exact route to take. The Big Gun explosion is not survivable, regardless of your health level and armor strength. Now, push the flashing green button in the pedestal by the window overlooking the laser. Immediately turn and run to your right (north) and follow the passageways to the room where you defeated the hovering monster. The automatic double door to the right is now open. Run through it and down the stairs as the mechanical voice counts down toward zero. Dash into the waiting underground tube shuttle car as fast as you can and get it moving by pushing the green bar near the front end.

Secrets
The Big Gun area has no secrets.