Pros:

A story!
Reasonable story at that, with logic to each step along the way
Its very own one-off Man On The Edge (each day gets closer to losing his head)
Some nice touches with the suicides
Huge area not just a tube
A witch in a dark maze of twisty little passages, all different, part of my suggestion for how to make a scary campaign!
A visible helicopter arrival and highlighted access route
Resupply just when I was starting to worry about it
Long without repetition or grind

Cons:

Glowing golden desert with incandescent milk river in the bottom of the canyon
Bullet-proof air, particularly in the open-sided jeep
Ladder to helicopter is partially underground and the glow shows it
One place where I felt like I could be there an hour waiting for a moment to climb out of the hole, which I could have chanced with human team-mates but not with bots
Lost all three bot team-mates because the one place I didn't expect the pick-up was the helipad that already had a burning heli on it, we were at the supply room and they stayed there to fight rather than running with me when I saw where the heli went.

Conclusion:

Beautifully done. Highly recommended. Just be sure to leave the supply room and head for the helipad before you kill the second tank in the finale.