Is there an easier way to kill the trolls?

Three shots in the head with the sniper rifle should make them fall to their knees, so then you can keep slashing at them.

When you shoot them, keep running throought the trolls legs and go to the other side.

Repeat this proccess.
Also, you have to slash the plagas on the trolls back.

For the first one, it's pretty simple, avoid being hit while attacking him with something strong, once he kneels over use something fast and shoot away at the "wormy thing". I find shooting them to faster and easier.

Second one in that canyon you don't have to fight, just run past him, shoot down the door, get the key, and run like hell.

The third time you run into these suckers should be in that lava room where you have to fight two. To kill these guys, just wait till 1 is on the trap door and pull the switch up on the lift. This automatically kills him, giving you enough free space to kill the last one. Just use what ever tactics you used to kill the very first giant to finish this guy off.

The so called 'troll's are actually called El Gigante's. Shoot them in the head, no where else. If A gigante is close to you, throw a flash grenade as it will blind him, and run through his legs. While the Gigante is still Blinded, unleash a barrage of bullets into his back. The Shotgun, the Sniper Rifle, and the TMP are the guns I used to kill the Gigante. Here is a cheat. If you have 30,000 dollars, and enough room in your bag, go talk to the merchant and but the Rocket Launcher from him. Now, keep shooting the gigante till the Plagas in his back comes out, and then blow it up with the Rocket Launcher. The rocket launcher will kill ANYTHING in one hit.

The way I did it was to buy a Rocket Launcher every time I knew they were coming. The first time they show their ugly, gray heads, you have ample warning from the letter you got at the beginning of Chapter 2-1. You also pick up tons of cash before the fight. The second time is optional, but it's either him or a couple of chainsaw ladies, so I pick him. You got loads of cash from fighting in the cabin, so use that to pick up a Rocket Launcher and nail him with a picture perfect shot to the head. The final time these @$$holes show up, there's 2 of them. Drop one in the lava pit, then shoot the other with the launcher. And then ye shalt never be troubled by thy abominations. Note: If you can't get a launcher(whether it be the space in your case or the cash in your wallet) then unload all your ammo into the dumb@$$'s back. Also, if you fight him in the canyon, DO NOT LET HIM GRAB ASHLEY! She'll easily die from his grasp, and still be more annoying then a truckload of flies(Don't ask how I made that Comparison...)

The el-gigante. I call him a brainless twit. Anyway to kill him just shoot him on the head with the shotgun a little. Then he will fall. Then climb him and cut that dang parasite. You can also use the rocket launcher.

If you are fighting him the second time Ashley will point towards the boulder. Let him grab her and quickly shoot the boulder. He should get hurt pretty bad.

In the last fight again'st these b!tch&$ drop the first one in the lava pit and then blow the other one to pieces with the rocket launcher.

Buy a rocket launcher and shoot o promise he is going to die