Nothing much, just a little extra thing they put in the game. On level 20/21, as you enter the level bomb-jump onto the small ledge just to the left and it activates a red-bomb gate below. Use one to get to level 22. The board then comes up saying below is the end of the world. Ignore it and you come to level 0 in Adventure mode. However, a few pears have made themselves at home. You still have unlimited lives, so it's no problem (use the black bomb gate to kill them). After you kill them all, you can't drop to the next level (invisible platform) and the bucket can't be destroyed.
In the learning mode, there is a secret passage (to go to level 20). What's the meaning of it?
