First, if you hit the bucket at the beginning and then go into PD 0, when you come back out it will be impossible to go through the secret passage, but you can enter level 1.
Second, If a frozen bobble is falling down against a wall, it can unfreeze and begin to move along the wall.
As a side note the coin on level 0 can only be gotten once, either before or after PD 0.

in levels like 49 (with stairs).
level, and smashed the wall to the next level. Normally you would jump-roll back, but I jumped just before hitting the wall, and got stuck in the corner, shaking all the screen and waking the fireball. So, don't do silly things there 
or
you cant see the letters on on the top of the screen like on 2-strange noises are coming from the lowe levels lv or 16-its getting darker
is actually Master System Controller, not a NES Controller, as the game says. Same for the supposed Master System Controller at PD64. Yup, it's a NES one. 