Duke Nukem 3D/Lunar Reactor

Restricted area
At the start of the area, you can collect the shotgun in the weapon locker to the left of the starting room. The first hub will have a few sentry drones that will attack, as well as troopers to your left.

This hub has three doors - the restricted area to the left, crew quarters to the right (requiring the blue key), and the reactor core ahead (requiring the yellow key). There are also a few vents as well that allow you to traverse the map, but they are blocked until you go through the locked doors.

To get the blue key, head to the restricted area, and defeat the commanders that block the path to the washroom. There are also a few captains within the main washroom area, and troopers hiding within the stalls. The blue key is located in the second stall, but you can also collect an RPG, and find a new vent path (which is currently closed.)

Crew Quarters
The crew quarters is the right-hand path from the entrance, and requires the blue key. However, Assault captains will arrive by the time you re-approach the door.

At the end of the first corridor is a mini-battlelord. It should die with at most 10 RPG rounds.

A chaingun is located at the end of the crew quarters, but collecting ti will bring reinforcements. To continue, jump into the red chute in the right-hand sleeping area, flip the switch, and run past the two walls before they crush you (being careful not to run off the cliff.)

From the cliff area, make a running jump to the other side, where you see an entrance. You will collect the yellow key here. Run down the corridor until you see troopers; press forward and the corridor should begin to collapse. Run back to avoid the collapse and explosions, and return to walk through the vent that is on the verge of collapsing.

When you reach the slime area, quickly run to the exit, located across from the barrels. Grab the boots before attempting to get past the gear. The spinning gear conceals the red key (required to exit the local area), as well as assault captains. With the red key, return to the central hub.

Reactor core
After opening the yellow key door, you will encounter two mini-battlelords. If you can't defeat them, run to the staircase to the right, and head down.

Head to the other side of the room, open the core, and destroy it with a rocket. When you go into the exit, wait at the mirror as the explosions approach from behind, dodging attacks as necessary.

Secrets

 * 1) After heading outside, there is a secret door to your left, containing health and chaingun ammo.
 * 2) In the place where you need to flip a switch to get through two crushing doors, instead, run to the alcove visible slightly to the right. Turn around, and open the corner wall to retrieve an atomic health.
 * 3) Outside, there is a small cave. It is located directly below the gun turret, and requires the jetpack to safely enter and exit. It contains a shrinker, and an easter egg.
 * 4) If you can climb on top of the collapsing vent past the yellow key, you may be able to jump into the cave to the left. You can get armor and atomic health there.
 * 5) In the red key room, open one of the computer panels to retrieve a holoduke.
 * 6) In the reactor core area, there is a raised platform on the right.
 * 7) In the reactor core area, there is a raised platform on the left.