Numbered bubbles:
Enter ASH as a password.

No attack bubbles:
Enter SOX as a password.

Final level:
Enter ACD to play level 8 under the easy difficulty setting, BCD for the for the medium difficulty setting, or CCD or the hard difficulty setting.

Level	Password
2	ADZ
3	GRT
4	GGF
5	HAS
6	HFD
7	JDI