Act 2: C2 - Indigenous Creatures
Move up to hear about the Rockworm, which is less harmful than you think. Just shoot the red fruit up to the right and then run past him. Soon you'll see vines on the left for ammo and a paper.
For the second worm, shoot the fruit and run by him for ammo and frags. Go right and all you have to do is shoot down the fruit up high, take cover, and then run when the worm goes after it. Take cover behind a block and from here you can use your boomshot and lancer to clear away the waves of enemies. The key to the fight is to take out anyone on the Troika turret, and you should have enough boomshots to do so. Once there is a break and the music is still going, run up to the ladder and be ready to slice up anyone else that jumps down.
Two boxes of ammo, but you shouldn't need to swap the boomshot for the other guns. Go up the ladder and look to the right as the wall explodes and two tickers run out; to the left is an ammo box. Take the blown open path and move up to see another worm. The fruit knocks down on its own, and then some drones come out of a hole further down. You may think you'll have to get into a long-range fire fight with these guys, but you don't. You can take cover on the worm, fire or toss a grenade to the enemies, then wait for one of your guys to charge them and you follow behind, or just shoot from the worm.
Move along until you hear someone mention snipers. At the second drill lift will be two Longshot rifles, but you may want to expend your boomshots before you swap it out. The idea of this fight is to move down the path and take cover behind a rockworm as it crosses the bridge. You will skirmish with the enemies as you stay behind this moving cover, with the occassional reavers flying over and by you. And when you get to the other side you can shoot an orange thing to blow the enemy's position up. The alternative is to stay where you found the Longshot and go through about 15 sniper rounds until everyone is dead; takes a while, but it works.
*NOTE: FYI, you click the RS to zoom in the sniper rifle.*
After that, choose your next path, and we will go right again. Here you can practice your sniping on some moving enemies below and a five that don't move, then grab the ammo and move up. Up the ladder you need to take cover and start tossing grenades towards the turrets. Your friends are on the right side, you are on the left. All I did was use my Boltok, but you can toss the many frags that are all over the place behind your cover. There are three turrets, but you can just stay on this side and handle what you can see.
When you see the reaver, hurry and get on a Troika, the left one worked for me, and mow it down. There should be a small pause in the action, then enemies will bang on the gate to your side, so get on this left Troika and mow down the diverse group of baddies, including the inaccurate Boomers. After that feel free to collect frags, but behind this left troika is a box of ammo and a scroll.
Exit through the gate and you'll see some allies drop in, but they come under heavy fire. From up here you could take out the troika and a mortar, or just run down the path and do it up close, which is the best way. Then quickly get on the troika and just mow down anything that isn't human; I guess ignore the reavers that hit and run. Once your guys move up a bit, be more cautious of where you shoot, then it will be over. After, box of ammo and then move along.