As you play through Scene 3-4, titled "Clothes Encounters," it's possible to receive an additional bonus point. Wait for the Wooden Dresser to wear the Bino head, and then knock it off. If you do it at just the right moment, a sound will indicate you received a secret bonus. However, the Wooden Dresser's heart will still be pink. It will put the Bino head on once more, and you can knock it off again for a second bonus. In this manner, you can acquire 5/4 bonuses in the stage, and 40/39 in the entire game (assuming you collect everything else as usual).
Hard Mode (or 1-hit death mode)
At the title screen, press Start once, then leave the cursor on Start Game. Just like the stage select code, press C, A, Left, Right, B. You will hear headdy say Nice when you've entered the code correctly. Then press and HOLD START. Continues holding start until you see the Opening Demo scene appear. Now you can release the start button and continue as normal. Be warned, One hit is all it takes to kill you now.
Head Animations
At the title screen select ''Options'' and press: C, A, Left, Right, B. You will hear ''NICE'' when you've entered the code correctly. Then press START to view the head animations.
Secret final scene
After the end credits has finished rolling you are prompted to enter a 4 digit secret code on a keypad. The valid code is different each time the game is played , complete the basket ball mini game four times while going through the game to determine your games secret code.
Stage Select
When the title screen appears, press START once. Leaving the cursor at Start Game, enter the code: C, A, LEFT, RIGHT, B. If you hear a sound, you've got it! Press START and you'll access the Stage Select! Just choose your level and stage. Then press START to play! (Note: This trick was done on an early version of the game. It may or may not work on later versions)