In the second room after riding the gondola up and down the large hill covered in spikes, there is a ledge with a small red potion. Walk up to the corner, crouch, and you will continue walking under the hill. Go through the door, and ride the gondolas across to the other end. You will emerge on a ledge at the end of the third room, right before the boss.
Last level w/ 30 lives
Match the colored squares on the password screen and press Start.
Temple Infernus Shortcut to boss
In the first room, go to the right, taking out enemies along the way. In second room, do the same, but do NOT go to the next room. About halfway through the room, (after the first green moving block and fire pit) there will be a platform at the top with a magic restore potion. To get there, the easiest way is to jump on the second green block as it moves toward you, and then use that to jump up to the platform. When you get the potion, press and hold DOWN to crouch and then, while crouching, go to the right. You will crawl through the wall and into a secret part of the room. Going right will teleport you into a room with two enemies that crawl along the walls; you can either dodge them or kill them with magic. The only exit to the room is in the upper left corner. It will take you directly to the boss.
NOTE: When you first enter the boss room, the health and magic bars will look like they have the max amount but are empty, and the lives and crystals will both be x99. When you first get hit or use magic, however, everything will change back to normal.