Successfully complete the game to unlock the Extreme difficulty setting.
If you are taking heavy fire and would like to replenish your health (if you have Thermal Energy), get into the nearest VS. While it is doing the startup animation, you will be invincible for about five seconds.
If there are a lot of Akrid or other things chasing you while driving the sled VS, do a boost jump. While riding around, you can also jump snow piles and get air.
When the battle first begins, notice the VS will fly around, doing various little spinning attacks. Fly towards him, then do a horizontal slash when next him. This takes a rather sufficient amount of health from the Boss. Occasionally when doing this you can also inflict a second hit, but be cautious of the homing missiles. The Boss will dart around shooting little lasers at you. To avoid them, simply follow in his direction to miss the attack entirely. Be aware, when the Boss reaches around 30% health it will call up two laser weapons. These will do massive damage if they hit you. One is horizontal, and the other is vertical. Notice when he gets ready for this attack he will throw his arms forward. This is your cue to get as far back as possible. The range on the lasers are fairly weak. When he is done, he will stand still for a brief moment and shoot missiles from his shoulders. Usually this is your cue to go in. The Boss does not have much of a pattern. Approximately nine well placed slashes are required to defeat the Boss.
First, gather up as much Thermal Energy as possible. On your way up the mountain make sure to destroy all of the Akrid hives. Get the rocket launcher on the metal slab coming out of the mountain. You can also grab the large VS laser if you want a back up. Then, climb to the top of the mountain but do not go into the cave. Stand at the top and wait for the moth to fly over you. Aim at the orange weak spots then shoot the tail part with your rocket launcher about two times. After the tail falls off do the same to the wings. A few more weak spots should appear near the top of his head. These are easier to hit with a charged laser shot. Once you defeat the giant moth he will crash into the side of the mountain.
First, gather as much Thermal Energy as possible before you fight the worm. To get more Thermal Energy, destroy the surrounding heat tankards and activate the outpost. If you need more Thermal Energy, just kill the surrounding flying Akrid and their spawn points. Get a sled VS and attach either a rocket launcher or gatling gun (recommended). Ride it just to the entrance of the Snow Plain. If you ride it any further the worm will knock you off and destroy the VS. Once you get off the sled VS, take off the weapon you brought with you. The gatling gun is recommended because if you miss you can adjust your aim and keep shooting him unlike the rocket launcher. Wait until he emerges from the snow and be ready for him to either growl or charge at you. If he charges and hits you, you will die. You can either roll to the left or right. After the roll aim at his sides and you will see several weak points. Shoot at them until they explode and reveal a reddish boil. Continue to do this until they are all gone then switch sides. Once he is hurt enough he may start shooting flaming balls that explode from his backside; be ready to evade them. Once again you will see more weak points. Do the same thing as done with his head side and he will eventually die. When he dies he will leave behind a large deposit of Thermal Energy. Note: The worm will re-appear no matter how many times you kill it.