Start through the door on the right from your spawn point. Spirit Walk through the force field.
The console's passcode is written on the floor. Enter 2432 to disable the force field.
Find a health station and acid ammo through the crawlspace on the left before walking through the door ahead.
Find Jen held in some sort of stasis field.
Enter this crawlspace on the right.
A pair of hunters patrol the other side of the crawlspace.
Plasma ammo is nearby, so you might as well use up what you've got. Take down the pair of hunters plus this turret down the left corridor.
At the other end of the corridor is a door leading to two mutilated humans and the plasma station. The locker on the left holds Auto Cannon ammo.
Proceed beneath the turret you just shot out and through a door to the force field on the left. Spirit Walk through, then disable the force field at this console.
Take out this mutilated human then use the dismembered hand on his console.
Meet your first mutate. Work fast to defeat him before a second is released.
Once the mutates are down, this pair of hounds attacks. These guys like to get close, so the acid gun works particularly well against them. Two spores are available for healing.
Exit through this now-unlocked door.
Spirit Walk through this force field and crawl into the subfloor below.
Emerge out the other side then hijack this console to open the door ahead.
Enter the portal on the right then Spirit Walk to the console on the left. Neutralize the mutilated human with your bow then use the console to move the portal.
Find health and ammo in the portal room then exit through this door.
Destroy this turret then find rifle and acid ammunition on the pipes to the left. Ascend the walkway.
Drop through this blue portal.
Defeat a pair of hunters then ready your Leech Gun before stepping through this portal. Rush forward to leech plasma from the station ahead. (Lightning ammo is available just to the left if you prefer.)
Four mutates emerge one at a time. Again, work fast to defeat the active mutate before the next is released.
I wasn't fast enough and had to battle two at the same time. My plasma depleted, I used a grenade (Auto Cannon secondary fire) while Talon provided cover.
Find this crawlspace across the room from the plasma/lightning stations.
Find ammo in the locker on the right. Step forward to hear more Art Bell -- this time his caller is the Keeper! The Keeper announces that the "Dark Harvest" is at hand.
Fill up on health and ammo, then exit through this portal.
Pass through another door to find Jen here. Use the console on the right to free her from the stasis field.
Receive a message from Elouit on this screen.
Health and ammo are through the door on the right. More ammo and the exit portal are through the door on the left.