Start a new game and reach level 2. At this point upgrades will be available. Purchase the health upgrade to take your health to 235. On level 2 (first star) you need to get the enemy's health low enough so that you can reliably end it with one word. Shuffle the letters until your health reaches 1, then kill the enemy. It does damage of either 15 or 18, so it does not always take you down to the 1 health requirement. You can replay this until you get lucky. If you already obtained all upgrades and do not want to start a new game, replay level 3 and hit the first monster a few times while avoiding the crystal letters. Do not kill it until it brings you down to three points of health remaining. Then, kill it and continue to the next monster. Hit it lightly with a three-letter word and allow it do two points of damage to you. Then, kill it and beat the gem pile. Progress through a new game until you have enough crystals to upgrade your health three times, to 305 health; and your armor twice, to 4 damage reduction. Consider only doing quests to get crystals faster. Return to level 1, "First Star". Hit the ghost with some small words until its health is low enough that you can eliminate it with one more word. Select "Swap" until your health is 1, and then use one additional good word to eliminate the ghost and break the crystal pile. Remove all healing items and go to this first star in level 3. The first enemy will do 9 points of damage to a character with maximum armor. Damage it to the point where you would be able to finish it with a single hit, then swap tiles until your health is low, at an odd number. Then, kill it. The second enemy will do 2 points of damage against maximum armor. Hit it until its health is low, then allow it to drop your own health down to 1 before killing it.
