Originally Posted by Capn Doug
2nd playthrough (20-45 minutes): Play on Pro and DO NOT TOUCH the unlock everything cheat since you are going for the good ending. Play through the first level until you unlock fireball, lock it to a button, then skip ahead. Keep skipping levels until you get to a level called the Two Towers where you see a yellow crystal in front. It is important to get that before you skip that level since it will get you enough souls to buy what you need later (you will need at least 450,000 souls, Entrance to the Castle also gives you a lot of souls). When you get to the level Dark Temple, kill the boss there and get the only story based achievement aside from beating the game and purchase Light Form, Light Blade and Ray of Light (they won't be available until you purchase the previous one). Skip ahead to Finale and use the Lightform/Ray of Light method to kill the final boss and unlock the achievements for beating the game and the achievements for the good endings. Killing the Dark Temple boss is actually the hardest thing to do in this method, but fireball will help, as will wearing the regen suit. A few tips, though. The biggest issue is the slow moving energy ball that he will fire at you. You can't out run it, but you can shoot it and destroy it. Because you have the regen suit, you can basically out wait the boss by hiding behind a pillar and waiting for your health to come back.
Just want to add a few things. When you start and you use the Skip Level cheat code for first time, DON'T just skip to next level. Defeat the boss from the hall way without getting hit, this will give you 25K souls. Then run around the room and smash all statues and vases there. Once you smash everything you will have over 1 mil souls. Then you can skip to the next level, DON'T walk thru the door because it will take you to the last level but you won't have the skills needed to defeat the final boss.