Chapter 18: Mount Doom

Walk up, break the two brown boxes below the ledge, build a ramp, then walk up ahead. Frodo can't jump here, so use Sam to jump across the island in the lava, then use the rope to pull down rocks so Frodo can walk across. Have Frodo stand atop the first platform that you'll see after you walked across the lava rocks. Switch to Sam, jump up the bars, pull yourself up to the very top, use the rope to climb up the ledge, stand atop the platform on the ledge to make Frodo's platform go up, walk across using Frodo. Use Frodo's phial to light up the dark cave, push the rock inside, use Sam to dig a rock, throw the rock at the target above, cross the rocks to the next area. Avoid the burning flames, then use Sam to climb up the bars, walk across the lava rocks as Frodo. Smash the objects blocking the cave, cross the cave using Frodo, use Sam to pull down the rocks above, cross the rocks again. Make Frodo stand on the platform at the right, use Sam to jump up the middle rock and then to the left platform to elevate Frodo. Use Frodo to walk at the plank on the left, then fall down to the left platform to make Sam go up. Use Sam to jump across, dig up and build a bridge for Frodo, then walk across. Use Sam's rope to pull down a huge rock, then walk up. Smash the objects near the slider, build a pillar, push the pillar to the left side, make Frodo stand at the right platform, use Sam to jump up the ledge above Frodo's platform on the right, use the rope to make it across the left platform, wait until Frodo moves to the top of the pillar, then push the pillar to the right. Switch to Frodo, light up the cave, walk to the right, then smash the rock. Switch to Sam, enter the hatch, go down the lava floor below. Use Frodo to enter the hatch as well, then go to Sam's area.

Simply pick up the rocks and throw them at Gollum. If one of the two Characters is being mauled by Gollum, switch to the other character and smack Gollum with a stone.

The idea here is mash Square with Frodo when he is being attacked by Gollum. Once he's not holding Frodo anymore, use Sam to smash Gollum. You need to hit him with Sam to reduce his hearts. Each time he gets hit by Sam, he brings Sam down to a lower level, just build the platforms, jump up, rinse and repeat. For the final heart, once he lets go of Frodo, use Frodo to walk all the way to the rightmost area and build a platform using the silver bricks for Sam. Jump up and hit the schizo to end him.

Simply run down the path while avoiding the rocks blocking the way.

Congratulations on finishing the main story! Now onto the collectibles!