Gurumin: A Monstrous Adventure
Successfully complete the game on the Normal difficulty setting to unlock the Hard difficulty setting. You may also start a new game to access a bonus sub-quest and have all previously unlocked costumes, money, and the drill power-up available. Although you will have to find the Headgear again, they will be at their previous levels.
Successfully complete game on the Beginner, Normal, Hard, and Happy difficulty settings. Start new game and get the drill then return to town. You can find Popon in front of Fan's cake shop. Talk to her and you will be able to play as her.
Successfully complete game on the Beginner, Normal, Hard, and Happy difficulty settings. Start a new game and go to the final locked house in human town and enter "LEGENDARY" as a password to unlock Boss Rush mode. Note: Enter "yarushikanaiwane" as a password in the Japanese version in Hiragana/Katakana. Boss Rush mode allows all eight Bosses to be fought in succession.
Successfully complete Boss Rush mode to unlock the "Movie Viewer" option.
Successfully complete the game, then choose to start a new game. Then at the difficulty selection screen, hold L + R and press Left, Up, Right, Down, Left, Up, Right, Down, Left, Up, Right, Down. If you entered the code correctly, you will hear a sound.
Successfully complete the indicated task to unlock the corresponding alternate costume. Use the dresser in the corner of Parin's room to change costumes.
- Armor: Give 30 Gold Medals to Hyperbolic in Beginner mode.
- Chinese Dress: Get the good ending in Hard mode.
- Kimono: Set the system date between January 1st and 7th.
- Leopard Suit: Get the good ending in Crazy mode.
- Maid Outfit: Can be bought from the vending machine at Spinach Caverns - Shadow Grotto.
- Monkey Suite: Get the good ending in Beginner mode.
- Nurse Outfit: Successfully complete Boss Rush mode in Happy mode.
- Pajamas: Get the good ending in Normal mode.
- Princess Dress: Give 30 Gold Medals to Hyperbolic in Normal mode.
- Samurai Outfit: Give 30 Gold Medals to Hyperbolic in Crazy mode.
- Santa Outfit: Set the system date between December 25th and 31st.
- School Uniform: Get the good ending in Happy mode.
- Swimsuit: Successfully complete Boss Rush in Crazy mode.
- Vampire Outfit: Give 30 Gold Medals to Hyperbolic in Hard mode.
- Witch Outfit: Give 30 Gold Medals to Hyperbolic in Happy mode.
- Work Uniform: Successfully complete Boss Rush mode in Hard mode.
- Workout Gear: Successfully complete Boss Rush mode in Beginner or Normal mode.
- Chinese Dress: Get the good ending in Hard mode.