1. Run into that room ahead. Move fast to avoid the ceiling turret.
2. Inside you'll find an armor vest. Use the doorway for cover and destroy the turret. Continue through the door visible across the hall.
3. Duck behind these crates on the right and take out this ceiling turret.
4. Destroy this turret on the other side of the laser field.
5. Destroying the explosive barrel opens up a grate in the floor.
6. Follow the shaft, descend a ladder, then explode this barrel to open the exit.
7. Destroy another ceiling turret before riding this lift up. Note the large medkit.
8. Destroy this ceiling turret and grab the large medkit and ammo seen on the left.
9. Destroy a second ceiling turret, seen here on the left, before climbing over the dirt and continuing through the door in the center.
10. You're now on the opposite side of the laser grid seen earlier. Grab the armor vest on the left, the large medkit on the right, then continue through the door in the center.
11. Hide behind the crates in the center of the room and destroy all three turrets.
12. The neighboring room has four turrets, three of which can be taken out from here. The one in the center of the room can be destroyed by firing upon explosive barrels underneath. The one seen here can be taken with direct fire, as well as a similar turret to the right. Just be sure to avoid the blue sparks seen here on the left. Jump over the crate and into the the room once it's safe.
13. The fourth turret can be taken out by exploding the barrel seen towards the end of the hall. Continue through the door at the far end of the hall after grabbing the large medkit to the left of the lasers.
14. The water is electrified so keep your distance. Grab the ammo on the left, and avoid the temptation to grab the medkit on the floating crate. If you find a way to get the medkit, let me know.
15. Backtrack under the laser grid and through a door on the right to these stairs. Hop through that broken grate and descend the ladder.
16. Hug the right wall to protect yourself from the turrets above. Pop out and fire at the three turrets until they are destroyed.
17. A large medkit, armor and ammo are found here. Continue through the door ahead. Be cautious, as there are more turrets.
18. The two ceiling turrets and the malfunctioning laser grids can be bypassed by slipping behind these crates on the right, descending a ladder, climbing through the shaft to the other side then climbing up another ladder. I still prefer to destroy the turrets. Note the ammo on the crate ahead.
19. Approach this door and it slides open. One turret is on each side of the door. Note the large medkit on the crate. Continue to the right after destroying the turrets.
20. Explosive barrels take out the next turret. The one after that you'll have to destroy yourself.
21. Two more ceiling turrets as well as ammunition are found in this hallway. Continue through the door on the right.
22. Grab the large medkit from this crate then fight your way through that doorway on the left.
23. This guy will spawn behind you. He is slow and can be easily outrun if you prefer.
24. Destroy the ceiling turret on your right as you exit, then ramp up this debris and jump over the laser field.
25. Grab the large medkit and armor vest seen here, then jump-crouch onto those crates far-right to return to the other side of the laser field.
26. Continue through this door. Note the medkit and armor on the left. You can return for those once you need them.
27. Climb these stairs -- note the grate on this side is intact.
28. Destroy this armored guard on the right.
29. Jump-crouch across these crates and destroy a second armored guard. Move quickly to avoid the toxic orange vapor.
30. Don't try to jump over these lasers directly. Instead, jump to the indicated ledge first, then hop over the lasers. Crouch under the lasers beyond.
31. A medkit, an armor vest and ammunition are down the red steps. Another medkit is seen on the right. Activate the green console on the right.
32. Backtrack to this position and jump onto the indicated ledge before jumping over the lasers. You can now crawl under the lasers beyond and pass through the door. (Another green console just visible to the left can be ignored.)
33. Fight your way down this hall, using the crates for cover as you destroy the ceiling turrets. There is ammo on this crate on the right.
34. Pass through this door, search the room for health, armor and ammo, then exit out the bluish doorway beyond to load the next level.