Game secrets for Gameboy TMNT: Fall of the Foot clan

From Gamesages 
http://www.gamesages.com/gameboy/codes/tmnt_fall_of_the_foot_clan.html

Bonus Game:
To play the bonus games, go to the stage select screen. Press A, B, and Select
at the same time and you'll hear a tone. A question mark will appear to the right 
of the level 5 select. Select the question mark and you'll be able to play the 
bonus rounds.

Hidden bonus round in level 1:
Destroy the second oil drum and you'll get to play the number guessing bonus round.

Restore health:
If you need your life restored quickly, pause the game and then press Up Up Down 
Down Left Right Left Right B A. Unpause the game and your life will be refilled. 
This code only works once.