Before you fight the worm, gather as much thermal energy as you can. Get more thermal energy by destroying the surrounding heat tankards and activating the outpost. If you need more thermal energy, simply kill the surrounding flying Akrid and their spawn points. Get a sled VS and attach either a rocket launcher or gatling gun (recommended), then 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 you can adjust your aim and keep shooting him if you miss, 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, consider yourself dead. You can either roll to the left or right. After rolling, aim at his sides and you will see a number of weak points. Shoot at them until they explode and reveal a reddish boil. Repeat 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 sure to evade them. You will once again see more weak points. Do the same thing as done with his head side to finally kill him. He will leave behind a large deposit of thermal energy when he dies. The worm will re-appear no matter how many times you kill it. Also, the achievement for killing it will not appear until you complete the level.