It's the first time I play this game on the NES.
I played a lot on the arcade.
I use this site as a reference on how to get the special items.http://tjasink.com/g.../bb/items2.html
also this pagehttp://tjasink.com/games/bb/
I don't think that all of the arcade item and bonus points are available in the NES version.
For example, in the arcade, if you get to level 20 without loosing any life, you get to a level containing severals dimonds worth 10 000 points each.
If you go through the bottom hole a any level more than 10 time, you have the possibility to get 100 000 points by eating all the obkects on the screen.
One that work great:Try to get your tens and hundreds digits lined up. For example 10990, 270110
0. Blow as many bubbles as you can, as far as possible from the ennemies that are already captured in bubbles. Then pop all the ennemies, make sure that you don't hit any other empty bubbles before you do because it will increase your score by 10 making this trick not work. All the empty bubbles will change to fruits worth 300 points each. This way you can get 5000 or 6000 extra point at each level.
Always pop as many ennemies at the same time as possible: This will give you more points 1000 for one 2000 for 2 - 4000 for 3 - 8000 for 4 - 16 000 for 5 and so on. The fruits you get will also give you more points. Also when you pop more than 3 ennemies, you will get letters to spell EXTEND. If you kill 3 you will get 1 letter, 4 you will get 2 letters and do on. When you pop more that 3 ennemies but don't end the level, the letters will appear right away. If you don't get the letter in the current level, they will come back at the beginning of the next level.
Hope this help. If I think of any other I'll let you know.