To change the graphics to an alternate set, use the following password: 3297.
To reach the first bonus stage, play through Easy difficulty level in one go, without leaving a level and using a password once. For the second bonus stage complete stage 7 of Medium difficulty with less than 103 moves.
Easy:
Stage 01: 1234
Stage 02: 9941
Stage 03: 6765
Stage 04: 6799
Stage 05: 4365
Stage 06: 2665
Stage 07: 1436
Stage 08: 3663
Stage 09: 3153
Stage 10: 2984
Credits: 3232
Medium:
Stage 01: 4567
Stage 02: 6231
Stage 03: 5729
Stage 04: 5672
Stage 05: 7681
Stage 06: 9871
Stage 07: 9112
Stage 08: 6464
Stage 09: 4861
Stage 10: 3125
Stage 11: 2358
Stage 12: 4279
Stage 13: 6591
Stage 14: 7492
Stage 15: 9692
Stage 16: 8843
Stage 17: 6618
Stage 18: 5933
Stage 19: 4858
Stage 20: 3215
Credits: 5332
Hard:
Stage 01: 6789
Stage 02: 4991
Stage 03: 6116
Stage 04: 6184
Stage 05: 7346
Stage 06: 8982
Stage 07: 5731
Stage 08: 3987
Stage 09: 1167
Stage 10: 8992
Stage 11: 4536
Stage 12: 4811
Stage 13: 5297
Stage 14: 3151
Stage 15: 1335
Stage 16: 4488
Stage 17: 4662
Stage 18: 6627
Stage 19: 9883
Stage 20: 6338
Stage 21: 1686
Stage 22: 4384
Stage 23: 1561
Stage 24: 4492
Stage 25: 1756
Stage 26: 4391
Stage 27: 5423
Stage 28: 5943
Stage 29: 4456
Stage 30: 5115
Credits: 1995
Bonus:
Stage 01: 9715
Stage 02: 9435
