Big Eyes Mode: Complete the game with the difficulty set on Hard.
Easier Bosses: Near the beginning of the game, if you save the people in the lift then the bosses will be easier to defeat.
Mad Mode: Beat the game 3 times and save it. Next, start a new game from the saved game file. Near the health bar, the words Mad Mode will appear.
Secret Art: Insert your game disc into a PC and look in the "omake" directory for extra .bmp files or check out some .wav files.
Heat-Seeking Laser Gun: Complete the game twice and save it. Restart your saved game to get a heat seeking laser gun that fires 4 heat - seeking lasers.
Lab Card Passwords: Go to Janeau after getting the lab card from Rat's Place. When Eliot gives the lab card to Janeau, the password will be 0513.
Become Almost Invincible: Complete a game and save it. Start a new game using your saved game file and you should now have 200 Hassy Drinks in your inventory.
Passwords for Bank Cards: Use these passwords at the Bank of Kimara.