Level six breaks away from the traditional snow pirate enemy and introduces a new human adversary - the suited-up commando. These corporation-backed soldiers take a bit more oomph to down, but with smart weapon planning and, of course, our handy guide, this perpetually hazardous level should be no problem at all.
The moment you round the first corner, the music will kick up and you're gonna have a flock of soldiers chasing you down. If you keep your distance though, you can probably off at least one of the soldiers on the ground before the rest can get off a shot. Then it's time to worry about the Vital Suit guarding the nearby data post - he'll be raining bullets on you as other troops blast rockets from the distance. Your best bet is to zipline up to the VS, chuck a grenade straight down so it bounces around but stays on the VS' platform and jump away as the grenade explodes. One or two should do it. The other option is to use the rocket launcher and get in a couple of quick shots, but you'll want to save those rockets for an upcoming VS bastard. Another tip: smaller VS' like this can go down with machine gun fire if you aim properly. Shoot for joints, backs of legs, things like that.
After the VS is down, use one rocket to take care of the rocket-launching enemy across the path. Now that you've got time to think, let's grab some target marks, shall we? While next to your new data post, turn north and you'll spot the "T" hovering in plain sight. Jump off the platform, look at its southern corner and you'll spot a "U" as well. Easy, huh? Use another rocket on the missile turret ahead and climb the buildings there, up to the two T-ENG containers for the next token, floating atop a ledge to the northwest.
Leap down, use your last rocket on the new missile turret and zip up the first balcony along the north side. Detonate the barrels against the wall to find a VS rocket launcher - use it to finish off the missile launcher if it's still functioning, and also to clear the surrounding area of all these annoying enemy soldiers. Zip up again, activate the data post for some much-needed energy and grab the smaller rocket launcher in place of the heavy, slow-loading VS one you have now.
Just a few steps east will send a larger, more painful-looking VS your way. Duck-and-cover rocket shots work best. Three direct hits should put it down and leave you free to collect a few more target marks. The "H" is underneath the north side of the large archway, and you'll find a "D" inside the small room at the end of the outside path. It's hidden behind some boxes in the southeast corner. Continue through this building for a cutscene, then access to the most bad-assiest VS you've seen yet.
Once in the suit, you only need to worry about three things: First, the "E" located inside the first door, floating near the ceiling. Second, the "R" found near the ceiling of the second hallway. Finally, you'll want to notice the dinosaur-sized, iceberg-blasting insect that's tearing the building apart. Oh, and it kinda killed your dad.
Fighting the Green Eye is a bitch, no doubt about that. The tactic is simple (use the VS to burst the bug's many glowing patches), but Green Eye's icicle attacks and aggressive charging can keep you from getting even one shot in if you're not careful. Just keep your distance, use the Gatling and rocket launcher combo and it'll do down eventually. First it's the spots along its side, then there are four more spots on its head, and after a long and arduous battle, one large spot will appear on its forehead. This VS can hover-dash by pressing Y, so use the feature often. It can get you away from the ice attacks in short order. Combine this evasive move with the large center structure for defense against Greeny's two massive ice attacks - if you get tagged once, you're likely to get hit two to three more times by one assault.
Your T-ENG is in limited supply here, so be sure to pick up the blobs of it the Green Eye drops after sustaining damage. Again, it's a helluva fight, but after an attempt or two you should be cool.