Half Speed
Hold down 1 and hit reset to let the game run at half speed.
Invincibility
Press 2 or 6, then RESET. Now release RESET, then release 2 or 6. Scoring will be disabled though.
Secret Message
Hold down ? and hit reset to see the message: BEES BY ROSHA.
Voice Sound Effects
Press 3 or 7 and push the directional stick.